The cursive l I actually like. We learn to write that here at elementary school (at around the age of six). So if quoting, a handwritten font is nice. I use such in my nvim config as well. But AFAIK such a font is proprietary. Now, this fella's repo owner is CN, so I doubt they learned such at elementary school. It is also, like you said, weird since it stands out. If the rest also used cursive handwriting letters it would've been fine. So yeah, classic case of cha bu duo, or a quick personal hack you'd be embarrassed to share).

I used to work with a guy who configured his IDE to use some wacky all-cursive font and it was awful. Not just having to read code in cursive, but also ligatures for things like "=>". So with every bit of code I had to constantly figure out what the real characters were underneath all that crap on the screen.