Well, perhaps not _everything_, but bookmarks certainly could be.

With BookmarkFS, you can mount your browser bookmarks to the local filesystem, and manage them flexibly using file management tools and techniques.

For example:

    # Mount Firefox bookmarks.
    # - Replace <profile-name> with actual profile dir name
    mount.bookmarkfs -o backend=firefox,rw  \
            ~/.mozilla/firefox/<profile-name>/places.sqlite  \
            /mnt/firefox

    # Change working dir into the Firefox "Other Bookmarks" folder.
    cd /mnt/firefox/bookmarks/unfiled

    # Remove duplicate bookmark URLs (while keeping the first one).
    # - Install "fdupes" using your distro's package manager,
    #   or download from <https://github.com/adrianlopezroche/fdupes>.
    fdupes -dN .

    # Move all HN posts into the subdirectory named "Hacker News".
    find . -maxdepth 1 -type f  \
            -exec grep -l news.ycombinator.com/item {} \;  \
            -exec mv {} ./Hacker\ News \;

    # Mount Chromium bookmarks.
    mount.bookmarkfs -o backend=chromium,rw  \
            ~/.config/chromium/<profile-name>/Bookmarks  \
            /mnt/chromium

    # Copy the "work" folder from the Firefox bookmarks toolbar
    # into Chromium's bookmarks toolbar.
    cp -R /mnt/firefox/bookmarks/toolbar/work  \
            /mnt/chromium/bookmarks/Bookmarks\ bar

    # Dismount.
    umount /mnt/chromium
    umount /mnt/firefox

Cheers!