Multiple .so files? #584

While trying to reduce the size of a snap (snapcraft) package, I noticed that sqlite3, among a few other gems with extensions (nokogiri, ffi) have multiple .so files. After bundling into vendor/bundle, snapping, and installing the snap, this is what's in it:

$ find /snap/my-ruby-app/current/app/vendor/bundle/ruby/3.3.0/gems/  -name '*.so'|xargs du -sh
...
1.5M    /snap/my-ruby-app/current/app/vendor/bundle/ruby/3.3.0/gems/sqlite3-2.1.1-x86_64-linux-gnu/lib/sqlite3/3.1/sqlite3_native.so
1.5M    /snap/my-ruby-app/current/app/vendor/bundle/ruby/3.3.0/gems/sqlite3-2.1.1-x86_64-linux-gnu/lib/sqlite3/3.2/sqlite3_native.so
1.5M    /snap/my-ruby-app/current/app/vendor/bundle/ruby/3.3.0/gems/sqlite3-2.1.1-x86_64-linux-gnu/lib/sqlite3/3.3/sqlite3_native.so
...

It seems there's an .so file for each recent Ruby version like 3.3, 3.2, 3.1?
(Same goes for gems installed on the system itself under ~/.gem/ruby/3.3.3/gems/)

What's the purpose of these? I can't think of a reason, given that they're installed by and for a single Ruby version (3.3.5 in this case)?

Maybe off-topic, but I also noticed that some gems have copies (verified with sha1sum) of their .so files under ~/.gem/ruby/3.3.5/extensions/. What's up with that? Just asking in case anyone knows. I can't find any other info on this.

Thanks for any info or pointers.