Firefox / Tor Browser can export bookmarks to a much easier to parse JSON file (though the Manage Bookmarks window calls this a “backup”, and uses “export” to refer to the old not-quite-HTML format). There is a script to translate this JSON bookmarks file to Split Browser’s TSV format:
If you only have a .html export, you could use Firefox’s Manage Bookmarks screen to “import” it, then “backup” to JSON.