Describe the bug
Although the main sitemap for Janeway repositories is loading, the individual sitemap xml corresponding to subjects is not. This is probably due to Janeway looking for an "issue" (which repositories don't have) rather than a "subject".

Janeway version
1.5 RC4

To Reproduce
Steps to reproduce the behavior:

1. Go to the main sitemap page for a Janeway repository, e.g. https://dev.eartharxiv.org/sitemap.xml
2. Note references to "issue", not "subject"
3. Click one of the listed xml links
4. See error

Expected behavior
Sitemap links would properly load for each of the repository's subjects.