I would like to be able to open bookmarked pages --- potentially a large number of them --- in an unloaded state. By "unloaded" I mean the state that pages are in at startup in Firefox if you choose the "Don't load tabs until selected" option in settings. This is also the state that extensions like UnloadTab put tabs into after a period of inactivity.
So what I want is to be able to click a bookmark folder (not just one bookmark) and be able to say "Open all these pages in unloaded tabs". That means that tabs should appear in the browser UI, but the page data should not be loaded and no network traffic to the references pages should occur, Each page should then load one at a time if and when I switch to each tab.
I use the UnloadTab extension but as far as I can see, it doesn't provide any option for opening new tabs in an unloaded state, only for unloading existing tabs. I also can't find anything in the basic Firefox settings to do this.
(The reason I want to do this is to transfer a large number of tabs from one version of Firefox to another. I cannot transfer the profile itself or use Session Manager because the source version is old and has incompatible extensions, including Tab Groups Manager, which interferes with how the tabs are stored in sessionstore. What I want is a way to go into an old version of Firefox, bookmark a bunch of tabs, and then load the corresponding tabs into a new version of Firefox without actually loading all the pages.)