I'm trying to learn about typography and I made this image, but I wasn't sure this was the arm because it's at the bottom of the letter. Can anyone help, please?
I can't find a definitive resource especially identified to the "L" character. It's possible that you're also dealing with 2 parts of anatomy and not just one.
But here are some samples:
Edit 4/22/22: Here is another diagram that might be the closest to refining the definition by breaking that part of the character into two parts and not just one:
I believe these are commonly called serifs. Perhaps 'arm' or 'beak' are used too, I'm not sure how commonly used that is.