Represents an installed gem. This is used for dependency resolution.
Installed
sources sort before all other sources
# File rubygems/source/installed.rb, line 13 def <=>(other) case other when Gem::Source::Git, Gem::Source::Lock, Gem::Source::Vendor then -1 when Gem::Source::Installed then 0 when Gem::Source then 1 else nil end end