AR lower parts bubba question

[KCcactus]

I recently bought a used AR. The trigger was pretty gritty, so I changed it out today. That's when I discovered the hammer looks like someone took a grinder to it.
Anyone have any idea what someone was trying to do with this?

[nitrohog]

It looks like they were attempting to lighten it, I've seen people bob the "hook" off of the hammer before but the modification below the face is a new one to me.

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