Netscape bookmarks

Netscape kept its bookmarks in a file named bookmarks.html in the user profile directory. It was (kinda, sorta) HTML, with a weird doctype specific to Netscape and some offenses against HTML decency like odd nesting of elements. It used some particular combinations of tags and attributes to represent the bookmark structure. Specific items changed over time in different versions as new features were added, but the basic structure remained similar to allow bookmarks to be shared between different browser versions. The format remained in use in early Mozilla browsers before switching to the JSON-based format used in the current Firefox.

Doctype: <!DOCTYPE NETSCAPE-Bookmark-file-1>