Why not use regular marks:
- Extmarks endure changes to the buffer
- Valid cross-file (without being uppercase). Yes, could do a remap.
- Can assign numbers and have them persist without getting shifted
Why not harpoon:
- Can have multiple marks per file
Other alternatives:
- harpoon2
- crusj/bookmarks.nvim
- vim-bookmarks
- marks.nvim
- nvim-project-marks
- LintaoAmons/bookmarks.nvim
- tomasky/bookmarks.nvim
- arrow.nvim