This is mostly mathematics lectures for graduate courses on algebraic geometry, commutative algebra, and group/rings fields. There are also a few math talks at an undergraduate or high school level and a few short courses on other topics such as complex analysis, theory of numbers, modular forms, category theory, representation theory.
For the current list of courses, see the playlists page for this channel.
For anyone who wants to copy the format of the lectures, I'm using a program called OBS studio with a logitech webcam and a document camera and a yeti microphone. I use sketchpad for the thumbnails.