My text files still work. I have MUD design documents from when I was in high school (mid to late 90s). Org mode and Markdown are kind of eternal formats. Even

My text files still work. I have MUD design documents from when I was in high school (mid to late 90s). Org mode and Markdown are kind of eternal formats. Even if all the tooling dies, they still look decent. Basic HTML still works well enough as well. You can write a parser for XML pretty easily. HTML can also be processed and rendered trivially. I think we could collectively find some other technologies that are likely to be around in another 20 years. The simpler the file format the more likely it is to be around :) edit: A few more popped into my head. CSV. SQL schema + Data dumps (text format). The common theme to everything here is plain text. SQLite, although binary, is probably close to eternal. Git is eternal enough (recent HN post showed even POSIX shell is good enough to write a basic git client). JSON is easy to write a parser for as well. YAML.