@pankraz that package is part of a meta package called: librem5-base, that pulls default packages to be installed on a pureOS image for a Librem 5. And also sets some default configs.
It's not a gnome package per se.
Some of the packages that are installed using that metapackage are from gnome yes, but not all.
And that meta package; since it is not a gnome package, follows it's own version scheme.