Update its todo with remaining items.
Add changelog entry.
Simplified internals document to no longer be notes to myself, but
target users who want to understand how the data is stored
and might want to extract these repos manually.
Sponsored-by: Kevin Mueller on Patreon
An easy change now that supportedVersions is a list. Since v3 and v5 are
identical other than version number, just add v3 to the list.
This commit was sponsored by andrea rota.
