I don't think these methods are hotspots, and since gem specifications are sometimes serialized to yaml / marshal, I think we should remove as many instance variables as possible https://github.com/rubygems/rubygems/commit/40490d918b
changelog_uri
Bundle.*clean*
Bundler.environment
cgi
ln_s
target_directory
ln_sr
#ipv4_compat
Proc
Method