We are developing a commit policy app for Bitbucket that can verify branch names at creation/deletion (beside other features).

Options for formatting (e.g. by using HTML markup) the rejection messages are limited.

As you see in the screenshot below (from Bitbucket 5.11.1), each list element represents a veto with the summary and detailed message separated by a single space.

It would be great if we had more control over the formatting of this.

Same for branch deletion.

Actually, this problem is also present in case of merge checks:
https://jira.atlassian.com/browse/BSERV-4428