I've come across a few URLs that only show line numbers and not the file contents. https://gitweb.gentoo.org/repo/gentoo.git/tree/eclass/autotools-multilib.eclass https://gitweb.gentoo.org/repo/gentoo.git/tree/eclass/cmake-utils.eclass https://gitweb.gentoo.org/repo/gentoo.git/tree/eclass/bzr.eclass and probably a lot more. The plain views of each file works. Please look into this.
Fixed. Thanks for the report. Upstream fix is here: http://git.zx2c4.com/cgit/commit/?id=d3756bd7b00f9ad6adede3c7f956a25b22a2254a Already rolled out to gitweb.g.o, and those links in your description should work now.