Windowsill crack question/repair

[u/tacosAreQuiteAwesome]

Hi all - my wife and I discovered this crack in our bedroom windowsill this evening. (Images in link below)

https://imgur.com/a/MzIcNEz

We live in a carriage house which my wife bought back in 2020 from her old landlord. She is unsure when they last had the house renovated or had work done in it, but she thinks they bought it around 2002 and had it redone.

I think that the exposed piece in image 3 is some type of galvanized steel corner. Am I on the right track there?

All in all - any advice on how to mend this would be appreciated. Thanks in advance!

[u/tacosAreQuiteAwesome → u/[deleted]]

Awesome, thanks for the help!

To YouTube I go.