On the software side, ink is open source and has C# and JavaScript compilers, a Unity plugin and a separate IDE called inky.
Inform7 is not open source yet, although they had plans in 2019. As far as I can tell, it's a single app that outputs its own format that can be uploaded to https://www.ifarchive.org/
Disclaimer: I've never used either, ink just seemed more legible.
To add some detail, Inform 7 compiles to reasonably well-documented portable binary formats that have been standardized for decades, with the earliest versions dating back to Infocom days. There are a variety of emulators, including web-based. This is why games uploaded to ifarchive many years ago still work. Even if an old game’s source were available, they were sometimes written in obscure genre-specific programming languages that nobody uses anymore.
The binary formats are specific to the genre, which is pretty niche. Casual users are unlikely to have downloaded an emulator even if it’s easy to do, so a game will be bundled with one when it’s published to an app store.
But as formats go, it seems like a pretty remarkable success story for the long-term preservation of games, and it would be neat if there were a similar file format that were more general-purpose and more popular, much like we have for images, music, and video.
Inform7 is not open source yet, although they had plans in 2019. As far as I can tell, it's a single app that outputs its own format that can be uploaded to https://www.ifarchive.org/
Disclaimer: I've never used either, ink just seemed more legible.