This is an excellent extension, and it was exactly what I was looking for. The only small issue I had is that it cannot show timezone information. That is, I can't insert a time that contains "EDT" or "-0400".

Work flawlessly. Please only correct the help page to reflect the different shortcut configuration from chrome

Fantastic! This is exactly what i need! Custom format + input keyboard shortcut = winner!

Works well. I suggest you add shortcut to insert several types of formatting (d-y), (DD-yy-h-m) or (l j F y (G\hm) for instance.