The version in Aur is outdated. I downloaded the current version from Floorp's website but I couldn't install it.
Here is the content of tarbz2:
application.ini
browser
defaults
dependentlibs.list
floorp
floorp-bin
fonts
glxtest
gmp-clearkey
icons
libfreeblpriv3.so
libipcclientcerts.so
liblgpllibs.so
libmozavcodec.so
libmozavutil.so
libmozgtk.so
libmozsandbox.so
libmozsqlite3.so
libmozwayland.so
libnspr4.so
libnss3.so
libnssckbi.so
libnssutil3.so
libplc4.so
libplds4.so
libsmime3.so
libsoftokn3.so
libssl3.so
libxul.so
omni.ja
pingsender
platform.ini
plugin-container
precomplete
removed-files
updater
updater.ini
update-settings.ini
vaapitest
It worked, but only Floorp started, not installed.