Withdraw ID as an action is now implemented; if you reinstall the extension you can add “Withdraw ID” as an action and apply it in bulk. Please let me know ASAP if you run into any issues with it.
I also want to point out that the extension includes a full URL generator page that lets you apply ~all of the extended URL search parameters listed in the wiki through a user-friendly(ish) interface. Eg you can very easily create Identify or Explore URLs for all observations you’ve identified, in combination with any other taxonomic, geographic, etc search parameters you can come up with. You will still maybe want to bookmark ones you use a lot for ease of access but they are MUCH easier to make in the first place this way.