Would've be more useful if time was shown in minutes + seconds as on Youtube

As with all looping extensions that I've tested, this requires a video to be in its own window, and to not be in a playlist. This extension also causes the webpage to reload whenever the mode is changed. As others have mentioned, you must convert your desired start and end times into seconds. This seems like it would be an easy fix. Aside from the above complaints, the extension works well, and has the timing feature that other looping extensions don't.

I would prefer the main extension button to be next to the play button with a pop-out window for the options.

4/5 stars, does exactly what it says on the tin with a couple drawbacks.

Pros:
Precise text-based time inputs, rather than a drag bar(this is the primary draw of this add-on over other utilities, and the reason I installed it).
Repeat function works.
Unobtrusive menu icon expands when needed and can be minimized when unneeded without impacting function.

Cons:
Must input time in seconds, rather than the minute/seconds displayed on the video player.
Must be manually turned off after you finish using it or it will apply your previous settings to different videos(manifests as the video constantly looping itself at 0:00).

Firefox 72.0.1 / Windows 10 desktop

Be sure to deactivate Youtube's autoplay because otherwise the latter sometimes overrides the loop.
Also bear in mind that every time you activate/deactivate this (by pressing its buttons) the controlled video reloads.
I haven't tried it with multiple Youtube videos open/loaded/playing.
Otherwise it does its work.

PS Firefox Quantum 64.0 (64-bit) on Lubuntu 18.04 LTS.