L3 is the only thing used on desktops.
L1 on desktops requires Intel SGX, however, I haven't ever seen this implemented in reality. If anyone has seen it, please share.
Otherwise, L1 exists only on Android and iOS, AFAIK.
The article claims that you can't record HD content from Netflix with L3 DRM. IIRC, that's false. They require L1 only for 4k content.