Back in the days of film we used to write on the leader with a felt pen. You can buy stock footage of that. That's what it looks like to me.
You might be able to fake it using a character offset text animator and random opacity.
Amazing how ancient glitches are somehow resurrected as hip animation features.
You can write out some stuff (careful to stay on the line) on a piece of paper with a Sharpie and shoot it with a still camera. Import the image, scale it up if needed, set position keyframes for vertical or horizontal travel, render the movie (no motion blur!), import the movie. Now you can later the frame rate, blending mode, or apply additional effects.
I hope I don't sound like old grumpy man but most of this trendy new hip look given to video is incredibly boring to me. It reminds me of the first time I saw a switcher with quad splits and 3D wipes. Every commercial made by a local television station in the late 70s at every newscast was so filled with this new eye candy that the story got lost. There's no substitute for an original design that contributes to the story instead of just adding a bunch of "look at that effect" nonsense to the shot.
Sorry, didn't get any sleep at all last night and I'm a bit grumpy.