As you well know, the vanilla Linux kernel, the one on kernel.org, is mostly open source and free, but there are some parts, like some firmware and some drivers added by third parties, that are proprietary, closed source. However, for those who don't want those binary blobs, there is a "clean" and 100% free version released regularly with the latest kernel versions. Is about GNU Linux-Libre.
Alexandre Oliva has announced this release, therefore, it is already among us GNU Linux-Libre 5.16. It's basically a Linux 5.16 kernel with those non-free parts cleaned up and replaced with free ones. Blogs like mt7921s and rtw89 (8852a) WiFi drivers, ili210x touchscreen driver, i.MX DSP Remoteproc, qdsp6 audio driver, and some others from ARM64 architecture (AArch64) have been removed.
Apart from these changes to make Linux 5.16 a proprietary free kernel, GNU Linux-Libre 5.16 you have not given up any of the features and enhancements introduced in the upstream version, such as futex2 to accelerate video games with WINE, support for AMX (Intel Advanced Matrix Extensions), new features and improvements for file systems, AMT (Automatic Multicast Tunneling) support, update for Zstd (Zstandard) compression, support for Qualcomm Snapdragon SoCs 690, the new security patches added to this version, etc.
This GNU Linux-Libre kernel can be installed on any distribution, although for ease, the developers of this kernel modification also provide binary packages for Debian systems and derivatives, as well as for Red Hat and derivatives. In this way, you avoid having to download the sources, configure, compile and install the obtained binary, since you can use the package management tools for the installation.
More information about GNU Linux-Libre – Official site of the project