They are using a "screen recorder" and there are plenty available for linux:
He says he uses "simple screen recorder" on a daily basis and it never lets him down. It uses X11 and probably won't work if you use Wayland (try Kooha if so). I use xfce on Fedora and apparently the X11 to Wayland transition is "in progress" (for better or worse). I see notes about reverting to Wayland and statements that Wayland support is experimental.# enable RPM fusion. su dnf install simplescreenrecorderI already have RPM fusion enabled, so the above "just worked". I type "simplescreenrecorder" and it launches, warning me about an Nvidia driver "flipping" option that it wants to disable.
Tom's Digital Photography Info / tom@mmto.org