This simple js bookmark let you display the correct commit timestamp at github

Display commit timestamp at github as javascript bookmark

javascript:(function() { 
var relativeTimeElements = window.document.querySelectorAll("relative-time");
relativeTimeElements.forEach(function(timeElement){
	timeElement.innerHTML = timeElement.innerHTML +" -- "+ timeElement.title;
})
}())

Using Chrome, I had to change the shadow root of the innerText to get the desired result.

javascript:(function() { 
var relativeTimeElements = window.document.querySelectorAll("relative-time");
relativeTimeElements.forEach(function(timeElement){
	timeElement.shadowRoot.innerHTML = timeElement.shadowRoot.innerHTML +" -- "+ timeElement.title;
})
}())