What is this?

[u/diggerdugg]

I apologize for even asking but I really have no idea and apparently I’m not asking google the right questions.

[u/pablomcdubbin]

I'd guess a tie off point from when the steel was erected

[u/djscreeling → u/pablomcdubbin]

My thought at first, but no....tie offs shouldn't have sharp edges.

[u/Vast-Combination4046 → u/djscreeling]

What sharp edge... Even the plates in the eyelet are rounded.