The following error is happening when fetching the "tremor" package:

ERROR: tremor-20180319-r0 do_fetch: Fetcher failure for URL: 'git://gitlab.xiph.org/tremor/tremor.git;protocol=https'. Unable to fetch URL from any source.

It seems that Xiph has migrated a few of their repositories to GitLab recently and git.xiph.org seems to have been down for a while.

I am using the branch "zeus" and the related recipe is located inside meta-multimedia/recipes-multimedia/tremor/.