summary: I don't need all the functionality provided by Tab Mix Plus (TMP), but I very much want TMP's session-management (SM) capabilities: notably, the ability to {save, load, delete, rename} named groups of (window, tab) tuples. This SM power (and my large number of named sessions) is what keeps Waterfox on my main (Linux) workstation. Is similar functionality currently (Apr 2019) available via a Quantum webextension? details: I've been a Firefox user from day one, and before that a user of Mozilla, Netscape, and Mosaic. (If it matters, OS-wise I'm mostly a Debian Linux user, but also run Windows for particular software.) I have also striven to stay up-to-date with Firefox (et al) for all the usual reasons. Unfortunately I was forced off the "path of righteousness" by 57/Quantum, because I heavily rely on TMP's ability to manage groups of tabs and windows, at least for my main daily. I *do* run Quantum on some lesser-used boxes (esp those running Windows), and very much appreciate the improved speed etc. I've been following TMP's efforts to convert from XUL to WebExtensions with increasing dismay. I appreciate the difficulty of Gary's task, and that the majority of TMP users are more focused on tab-display functionality, so I can see why SM seems to be down the priority list. That being said, SM is what most matters to me, so I'd like to know (in order of importance to me, decreasing): Is/are there add-ons for Quantum that enable the user to 1. (required) {save, load, delete, rename} named groups of (window, tab) tuples. (I.e., NOT just save the current session on quitting the browser.) 2. (desired) import from an existing TMP session.rdf to whatever sessionstore the add-on uses 3. (desired) export sessions from whatever sessionstore the add-on uses to the TMP session.rdf format