Usually, browsers only support search of bookmarks in the website's title tag which is often not sufficient to find a bookmark.

Some browsers, like Safari, provide built-in support for full-text search, but can only be used for content that's already in the browser's history.

Bogrep imports your bookmarks from multiple browsers (removing duplicates), and then downloads and caches them in plaintext (without images or videos). These cached bookmarks are subsequently used for full-text search.