Open Source and Credits
Draft for legal review. This is a plain-language first version and has not yet been reviewed by a lawyer. Items in [BRACKETS] are details PosSum still has to fill in.
possum.ing uses software, fonts and data that other people made and shared. This page credits all of it, gives the license each piece comes under, and includes the notices those licenses require.
1. Our open source policy
- We only use what we can comply with. Before anything goes into the site (code, fonts, data, models, media), we check its license and confirm we can meet its terms for a public, commercial site.
- Permissive licenses by default. We prefer MIT, BSD, Apache-2.0, ISC, the SIL Open Font License, CC0 and CC BY. Copyleft code (GPL, AGPL) does not go into the site without a review of what it would require of us first.
- We credit everything here and in the code. Each entry below says what we use, who made it, its license, and where it appears. Source files keep their original license headers.
- We keep the license texts. The full notices are on this page and as plain text files under /legal/licenses/.
- We check again when things change. Adding or upgrading a dependency means updating this page in the same change.
- We fix problems quickly. If we've missed a credit or got a license wrong, tell us (section 11). We aim to reply within 5 business days and to fix or remove the material within 30 days.
2. PosSum's own code and art
Unless a file or this page says otherwise, the site's own code, art, writing, music, characters and game designs are © [LEGAL ENTITY NAME] (PosSum), all rights reserved. They are not open source. You can read the code in your browser, as with any website, but you need our permission to copy, modify or reuse it. Ask at hello@possum.ing; we often say yes.
We may open-source parts of the site later. If we do, the license will be stated in the files and listed here.
3. Software
| Name | Version | Author | License | Where used |
|---|---|---|---|---|
| three.js | r186 | three.js authors (Ricardo Cabello and contributors) | MIT | 3D rendering in the treehouse, the lookout and Wreck Deck. Vendored unmodified at /arcade/wreck-deck/vendor/three.min.js, with its license header. |
| qrcode-generator (QR Code Generator for JavaScript) | 2.0.4 | Kazuhiko Arase | MIT | Draws the QR code on Elizabeth's contact card (possum.ing/hi). Vendored unmodified at /hi/vendor/qrcode-generator-2.0.4.mjs, with its license header. "QR Code" is a registered trademark of DENSO WAVE INCORPORATED. |
Everything else that runs on the site, in the browser and on our Cloudflare Worker, was written for PosSum.
4. Fonts
All fonts are self-hosted from /fonts/, so your browser never contacts a font service. They are the unmodified latin-subset WOFF2 builds published by Fontsource (v5.3.0) of the Google Fonts releases, and every one is licensed under the SIL Open Font License 1.1. Reserved Font Names are noted.
| Family | Designer | Copyright | License |
|---|---|---|---|
| Archivo | Omnibus-Type | Copyright 2020 The Archivo Project Authors. | OFL-1.1 |
| Baloo 2 | Ek Type | Copyright 2019 The Baloo 2 Project Authors. | OFL-1.1 |
| Courier Prime | Alan Dague-Greene (Quote-Unquote Apps) | Copyright 2015 The Courier Prime Project Authors. | OFL-1.1 |
| DotGothic16 | Fontworks Inc. | Copyright 2020 The DotGothic16 Project Authors. | OFL-1.1 |
| EB Garamond | Georg Duffner, Octavio Pardo | Copyright 2017 The EB Garamond Project Authors. | OFL-1.1 |
| Fraunces | Undercase Type (Phaedra Charles, Flavia Zimbardi) | Copyright 2018 The Fraunces Project Authors. | OFL-1.1 |
| Handjet | Rosetta (David Březina) | Copyright 2018 The Handjet Project Authors. | OFL-1.1 |
| IBM Plex Mono | Mike Abbink, Bold Monday, for IBM | Copyright © 2017 IBM Corp. Reserved Font Name “Plex”. | OFL-1.1 |
| Instrument Serif | Rodrigo Fuenzalida, Jordan Egstad (Instrument) | Copyright 2022 The Instrument Serif Project Authors. | OFL-1.1 |
| JetBrains Mono | JetBrains (Philipp Nurullin, Konstantin Bulenkov) | Copyright 2020 The JetBrains Mono Project Authors. | OFL-1.1 |
| Literata | TypeTogether | Copyright 2017 The Literata Project Authors. | OFL-1.1 |
| Newsreader | Production Type | Copyright 2020 The Newsreader Project Authors. | OFL-1.1 |
| Pixelify Sans | Stefie Justprince | Copyright 2021 The Pixelify Sans Project Authors. | OFL-1.1 |
| Press Start 2P | CodeMan38 (Cody Boisclair) | Copyright 2012 The Press Start 2P Project Authors. Reserved Font Name “Press Start 2P”. | OFL-1.1 |
| Schibsted Grotesk | Bakken & Bæck, Henrik Kongsvoll, for Schibsted | Copyright 2023 The Schibsted-Grotesk Project Authors. | OFL-1.1 |
| Silkscreen | Jason Kottke | Copyright 2001 The Silkscreen Project Authors. | OFL-1.1 |
| Space Grotesk | Florian Karsten | Copyright 2020 The Space Grotesk Project Authors. | OFL-1.1 |
| Unbounded | NaN | Copyright 2022 The Unbounded Project Authors. | OFL-1.1 |
5. Data and methods
| What | Source and author | License or terms | Where used |
|---|---|---|---|
| Bright-star positions, magnitudes and colors | Star catalog files from d3-celestial by Olaf Frohn, compiled from XHIP: An Extended Hipparcos Compilation (Anderson and Francis, 2012), based on the ESA Hipparcos Catalogue (1997). Repacked into a compact form for the site. | BSD-3-Clause (d3-celestial) | The sky above the lookout and through the telescope |
| Constellation line figures | d3-celestial by Olaf Frohn, after the IAU constellation charts, with his modifications | BSD-3-Clause | Constellation lines in the sky |
| Sun position | Low-precision formulas from Jean Meeus, Astronomical Algorithms (ch. 25), as used in the NOAA Solar Calculator | Published method, implemented by PosSum | The sky and the scene lighting |
| Moon position and phase | Low-precision series from The Astronomical Almanac | Published method, implemented by PosSum | The moon |
| Planet positions | E. M. Standish, "Keplerian Elements for Approximate Positions of the Major Planets", NASA JPL Solar System Dynamics | Published method, implemented by PosSum | Planets in the sky |
| Atmospheric refraction | Saemundsson's formula (as given in Meeus) | Published method, implemented by PosSum | Objects near the horizon |
| Weather (temperature, conditions, day or night) | Weather data by Open-Meteo.com, from national weather services listed on the Open-Meteo licence page. We round the values and turn weather codes into short descriptions. | CC BY 4.0; Open-Meteo terms | Call box weather |
| Air quality (US AQI) | Open-Meteo Air Quality API. Contains modified Copernicus Atmosphere Monitoring Service information 2026 (CAMS global and European air quality forecasts, including the CAMS ENSEMBLE data providers). Neither the European Commission nor ECMWF is responsible for any use of this information. | CC BY 4.0; Copernicus licence | Call box weather |
| Research paper titles and abstracts | arXiv API. Thank you to arXiv for use of its open access interoperability. | Metadata under CC0 1.0; arXiv API terms | Arcade news cabinet |
| Tech headlines and story summaries | Headlines gathered by techurls.com; one-to-two sentence summaries from each story's own page description, credited to the source | Quoted briefly with attribution; rights stay with each publisher | Arcade news cabinet |
The Arcade's seed questions and the quiz topics were written for PosSum.
6. AI model
| Model | Author | License | Where used |
|---|---|---|---|
@cf/openai/gpt-oss-120b, run on Cloudflare Workers AI | OpenAI | Apache-2.0, plus the gpt-oss usage policy | Writes and checks Arcade quiz questions. No visitor data is sent to it (see the Privacy Policy). |
7. Services
- Cloudflare: hosting, Workers, Workers KV, Workers AI, scheduled jobs.
- Shopify: store, checkout and customer accounts when the shop is live.
- Open-Meteo: weather and air-quality API.
8. Music and art
- "GRæLïêN" by PosSum (ft XLNCE), the record in the treehouse jukebox (
/audio/gralien-x-xlnce.mp3): used with permission of the artist. All rights reserved by its owner. [CONFIRM CREDIT LINE AND RIGHTS HOLDER] - The PosSum mark, the possum characters, the pixel art, the 3D scenes and the game sprites were made for PosSum. Game sprites and textures are drawn by code at runtime.
9. Built with (not shipped)
These tools help us build and test the site. They are not sent to your browser.
- Wrangler 4.151.1 (MIT OR Apache-2.0) and Miniflare (MIT), by Cloudflare: local development and deployment.
- Playwright 1.64.1 (Apache-2.0), by Microsoft: automated browser testing.
10. Full license notices
These are the notices the licenses ask us to include. Plain text copies: three.js, qrcode-generator, d3-celestial, fonts (OFL 1.1).
three.js (MIT License)
Show the three.js license
The MIT License Copyright © 2010-2026 three.js authors Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
qrcode-generator (MIT License)
Show the qrcode-generator license
The MIT License Copyright (c) 2009 Kazuhiko Arase Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
d3-celestial (BSD 3-Clause License)
Show the d3-celestial license
Copyright (c) 2015, Olaf Frohn All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Fonts (SIL Open Font License 1.1)
Each font family above comes with its copyright notice (listed in the fonts table and in the text file) and this license. In short: you may use, study, modify and redistribute the fonts freely, including in commercial work, as long as you keep the copyright notice and license, don't sell the fonts by themselves, and don't use a Reserved Font Name for a modified version. The fonts are provided without warranty.
Show the full OFL 1.1 text and font copyright notices
Fonts self-hosted on possum.ing (served from /fonts/, unmodified latin-subset WOFF2 builds from Fontsource of the Google Fonts releases). Each is licensed under the SIL Open Font License, Version 1.1. Copyright notices: Copyright 2020 The Archivo Project Authors (https://github.com/Omnibus-Type/Archivo) Copyright 2019 The Baloo 2 Project Authors (https://github.com/EkType/Baloo2) Copyright 2015 The Courier Prime Project Authors (https://github.com/quoteunquoteapps/CourierPrime). Copyright 2020 The DotGothic16 Project Authors (https://github.com/fontworks-fonts/DotGothic16) Copyright 2017 The EB Garamond Project Authors (https://github.com/octaviopardo/EBGaramond12) Copyright 2018 The Fraunces Project Authors (https://github.com/undercasetype/Fraunces) Copyright 2018 The Handjet Project Authors (https://github.com/rosettatype/Handjet/) Copyright © 2017 IBM Corp. with Reserved Font Name "Plex" Copyright 2022 The Instrument Serif Project Authors (https://github.com/Instrument/instrument-serif) Copyright 2020 The JetBrains Mono Project Authors (https://github.com/JetBrains/JetBrainsMono) Copyright 2017 The Literata Project Authors (https://github.com/googlefonts/literata) Copyright 2020 The Newsreader Project Authors (http://github.com/productiontype/Newsreader) Copyright 2021 The Pixelify Sans Project Authors (https://github.com/eifetx/Pixelify-Sans) Copyright 2012 The Press Start 2P Project Authors (cody@zone38.net), with Reserved Font Name "Press Start 2P". Copyright 2023 The Schibsted-Grotesk Project Authors (https://github.com/schibsted/schibsted-grotesk) Copyright 2001 The Silkscreen Project Authors (https://github.com/googlefonts/silkscreen) Copyright 2020 The Space Grotesk Project Authors (https://github.com/floriankarsten/space-grotesk) Copyright 2022 The Unbounded Project Authors (https://github.com/googlefonts/unbounded) This Font Software is licensed under the SIL Open Font License, Version 1.1. This license is copied below, and is also available with a FAQ at: https://scripts.sil.org/OFL ----------------------------------------------------------- SIL OPEN FONT LICENSE Version 1.1 - 26 February 2007 ----------------------------------------------------------- PREAMBLE The goals of the Open Font License (OFL) are to stimulate worldwide development of collaborative font projects, to support the font creation efforts of academic and linguistic communities, and to provide a free and open framework in which fonts may be shared and improved in partnership with others. The OFL allows the licensed fonts to be used, studied, modified and redistributed freely as long as they are not sold by themselves. The fonts, including any derivative works, can be bundled, embedded, redistributed and/or sold with any software provided that any reserved names are not used by derivative works. The fonts and derivatives, however, cannot be released under any other type of license. The requirement for fonts to remain under this license does not apply to any document created using the fonts or their derivatives. DEFINITIONS "Font Software" refers to the set of files released by the Copyright Holder(s) under this license and clearly marked as such. This may include source files, build scripts and documentation. "Reserved Font Name" refers to any names specified as such after the copyright statement(s). "Original Version" refers to the collection of Font Software components as distributed by the Copyright Holder(s). "Modified Version" refers to any derivative made by adding to, deleting, or substituting -- in part or in whole -- any of the components of the Original Version, by changing formats or by porting the Font Software to a new environment. "Author" refers to any designer, engineer, programmer, technical writer or other person who contributed to the Font Software. PERMISSION & CONDITIONS Permission is hereby granted, free of charge, to any person obtaining a copy of the Font Software, to use, study, copy, merge, embed, modify, redistribute, and sell modified and unmodified copies of the Font Software, subject to the following conditions: 1) Neither the Font Software nor any of its individual components, in Original or Modified Versions, may be sold by itself. 2) Original or Modified Versions of the Font Software may be bundled, redistributed and/or sold with any software, provided that each copy contains the above copyright notice and this license. These can be included either as stand-alone text files, human-readable headers or in the appropriate machine-readable metadata fields within text or binary files as long as those fields can be easily viewed by the user. 3) No Modified Version of the Font Software may use the Reserved Font Name(s) unless explicit written permission is granted by the corresponding Copyright Holder. This restriction only applies to the primary font name as presented to the users. 4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font Software shall not be used to promote, endorse or advertise any Modified Version, except to acknowledge the contribution(s) of the Copyright Holder(s) and the Author(s) or with their explicit written permission. 5) The Font Software, modified or unmodified, in part or in whole, must be distributed entirely under this license, and must not be distributed under any other license. The requirement for fonts to remain under this license does not apply to any document created using the Font Software. TERMINATION This license becomes null and void if any of the above conditions are not met. DISCLAIMER THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM OTHER DEALINGS IN THE FONT SOFTWARE.
Apache License 2.0 and CC BY 4.0
We do not redistribute Apache-licensed code or model weights; the model runs on Cloudflare's servers. The license is linked above for reference. CC BY 4.0 data is credited where it is listed, with a link to the license and a note of what we changed.
11. Report a problem
If you think we have missed a credit, used something outside its license, or listed something wrong, email hello@possum.ing with the subject "License". Tell us what it is and where you saw it. We aim to reply within 5 business days and will fix the credit or remove the material.