Differences to Other Tools
While Fquery tries to emulate the behaviour of equery, some exceptions have been made in cases where equery got it wrong.
The dependency query function takes into account the USE flags a package was installed with.
For example, dev-lang/ghc depends on dev-haskell/haddock only if the doc USE flag is enabled. Suppose it was not enabled at compile time.
equery has not implemented the changelog function yet, but emerge does have the --changelog tool. However, the two implementations differ.
You can limit the changes to list up to with Fquery, by passing in an argument after the package. Eg:
fquery c xorg-x11 xorg-x11-6.9.0
will only list changes between the installed and xorg-x11-6.9.0. This can be used to recover the emerge behaviour.