What is this fancy L with a curl on top, and how could I type it?
That character is SCRIPT CAPITAL L (Unicode U+2112), usually seen in by documents typeset with LaTeX for Laplace transforms or Lagrangian mechanics.
\mathcal{L} results in: .
In macOS, the closest you'd get is searching for the character L in the Character Viewer (option+command+space) and looking under Related Characters for SCRIPT CAPITAL L.
It's included in the STIX set of fonts, which comes with MacOS since OS X Lion.
Copying the character results in: ℒ
Another option is to go to system preferences > keyboard > input sources and add "Unicode Hex Input" you can toggle the "show input sources in menu bar", or bind it to a keyboard shortcut. Then, when you want to type it, hold option while typing 2112, and the L will be typed. You could also configure it in Automator with the recording function and add that to a keyboard shortcut or on the menu bar.
Check out this font: Lucida Calligra https://www.dafontfree.net/freefonts-lucida-calligra-f133249.htm
Apple products have good support for Unicode. Here is the math block since that looks like a equation:
- https://en.wikipedia.org/wiki/Mathematical_Alphanumeric_Symbols
Getting these edited in is usually easy one you know what character you seek:
- https://support.apple.com/en-us/HT201586
- What is the quickest and/or easiest way to infrequently type non-KeyLayout provided characters?
- How to access Greek symbols on macOS from a basic keyboard without copy/paste?
This may be a “Where’s Waldo” situation if you can’t find a type or font face that blocks the L instead of making it cursive/calligraphic.