Subarist Some time ago I thought about trying to create an extension to customise the deleted user, I was quite inspired by Github, there the deleted users appear with the name Ghost and an image of a ghost (what a surprise) and I thought it was funny.
Back to the topic, at that time I tried something with pseudo css elements for at least the avatar of the deleted user, but if I remember correctly I had problems later with users who had no avatar (with image), so probably the best thing is an extension.
