The CentOS 7 and CentOS 8 repositories are missing the repomd.xml file. As a result, it is currently impossible to install the CODE server/loolwsd.
(In reply to Johannes Reiff from comment #0) > The CentOS 7 and CentOS 8 repositories are missing the repomd.xml file. ... and hence I'd assume this a bug related to CentOS and not of LibreOffice.
But the repository in question is hosted and managed directly by Collabora, see https://www.collaboraoffice.com/repos/CollaboraOnline/CODE-centos8/. This situation has occurred previously, see https://bugs.documentfoundation.org/show_bug.cgi?id=118626.
*** This bug has been marked as a duplicate of bug 118626 ***