Description

This is a feature request which would fit well my tab archival and more specifically occasional tab retrieval usage.
I believe it would be rather simple to implement, and would highly promote compatibility and interoperability.

The functionalities in decreasing importance would imho be:

• Import a clean list of URLs from the clipboard
• Ignore any line with no URL on it
  Up to now, this is what the URLs list addon allows to do.
• With an option to enable it or not in the settings: Take into account tree structure by counting the leading spaces/tabs on each line (which would by the complementary to [Feature request] Option to reenable tree structure in plaintext copy #2090 )
• With an option to enable it or not in the settings: Ignore any url already open in the current window (which URLs list does too)

As I explained, I archive my sessions in plaintext. I know you have an extraordinary tab group management system, but I find it simpler not to rely on anything else than plaintext (maybe I'm wrong even, but up to now this is what has worked best for me)

Thanks for your extraordinary addon, which I can only invite people to donate for.

Edits: typos