1. Show chronology of individual visits.
I wish I could do this. The api only provides "HistoryItem"s:
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/history/HistoryItem

I'm not sure it's possible to have this information from the extension api, but I will investigate this a little more as there seem to be "VisitItem" which may be related:
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/history/VisitItem

2. Infinite scroll, or at least show more than 100 items per page.
Good idea. I'm using DataTables and they implemented this a while ago according to this post:
https://datatables.net/blog/2011-06-11

I will try to add an options page so we can tweak this a little more.

3. Option to show a sidebar instead of a new tab.
I suppose this can be done by following this:
https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/user_interface/Sidebars

But I'm not sure how it could fit into a sidebar tho

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Thanks for your suggestions and glad to see it helped. btw, sorry for the 1 year later reply. Looks like I didn't have any notification from Firefox. I just came here to release a new version to fix the date time column fomat ;)