The extension was indeed quiet for a while, but development has resumed and v4.2.0 was just released today.
Priority bug: You are right, this was a real bug. The "Keep newer tab" option was not working correctly due to a comparison error with uninitialized timestamps. It is fixed in v4.2.0.
New Tab pages: These are already excluded from duplicate detection. Both about:newtab (Firefox) and chrome://newtab/ (Chrome) are treated as blank pages and ignored. They will not appear in the duplicate list.
Trailing slash: Also already handled. URLs are normalized before comparison and trailing slashes are always stripped, so https://example.com/ and https://example.com are treated as the same URL.
If you are still using the extension, updating to v4.2.0 should fix the priority issue.
