Debian removes binary blobs from the kernel, putting them into separate microcode and firmware packages in non-free instead.

Intel places restrictions against reverse engineering the microcode, as well as it not being in the prefered original source. Both of these violate the Debian Free Software Guidelines, and thus it can only be in non-free at best.

Well it is a separate package because it is fundamentally independent of the kernel. For example, your Debian system might want to use a different kernel like GNU's Hurd, kFreeBSD, or NetBSD, so by keeping those packages separate, they can easily be used interchangeably. Also if you are on an AMD system, you wouldn't want Intel microcode, but you might still want the same Linux kernel.

Also another big issue issue is the Intel microcode is proprietary, so separating it from the kernel means that user could selectively pick and choose if wants to have a totally free system, which would mean not loading microcode updates with a libre kernel. This is done for instance with Parabola and Trisquel distros, which is needed to obtain FSF's totally free certification.

The star is Intel's weird house style for trademarks. They add a star to any third-party trademark, and in the footer there's "* Trademarks", which links to https://www.intel.com/content/www/us/en/legal/trademarks.htm...