Feature - display all marks across all files

[AIDIGIT]

Currently we can display all marks in the current buffer, but can we show all marks across all files even, like spelunk does?

I am thinking a potential use case can be the following:

• I am working on a feature x which requires 5 changes 3 files
• I can mark those 5 lines
• and then see all of them in a spelunk-like way
• It will show all marks, not just those 5 belonging to feature x. So maybe another feature would be to have something like an optional name/tag for the marks (that will be a different feature)