A proposito de iste extension

Short Demo Video
hold shift and right click on a paused or playing video to open the context menu. If the element you clicked on is a video the context menu should contain the "Copy Video Frame" entity. Note: if the entity is not shown, this likely means that the clicked element is not a video element or some other transparent element is overshadowing it. To get around overshadowing either the overlayed elements needs to be removed or the video needs to be brought to the top. Usually uBlock Origin's element picker or firefox's built-in element inspector will be able to help here.
Additional notes

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