Different web-browsers store bookmarks in different ways. However the overall answer would be the same and not as easy as would be desired.
In general the bookmarks will be stored either in an SQLite format database as used by Firefox or an XML file as used for example by Safari. These files will be located somewhere in the users Library folder for example look in the following locations.
Safari = /Users/username/Library/Safari/Bookmarks.plist
Firefox = /Users/username/Library/Application Support/Firefox/Profiles/???????.default/places.sqlite
These locations and therefore these files would normally be backed up by Time Machine.
In order to view the contents of these as stored in the Time Machine backup you would first have to restore them as normal via the Time Machine user interface by navigating to the relevant location and choosing when in 'time' to restore from and this would normally overwrite the current version(s) of these files. You could first move/rename the current versions before restoring a copy from the Time Machine backup. Then you would launch the web-browser to view the bookmarks. Theoretically you could view the raw XML code for the Safari bookmarks but you would have to use a SQLite database client to view the Firefox file and it would be simpler to use Firefox itself, you would still have to restore the SQLite database file first.