That is mindblowing to me. Full credit to the poster for becoming the canonical answer, but I'm not sure how I feel about Google picking comments without even some kind of page-rank-weighted attempt at deciding what is 'best'.
Google, please use less grug brained explanation of baseband processors [2]. ty
I think the parent comment is almost more informative.
"Baseband is the firmware that controls the cellular radio functions of an Android device. It is responsible for things like connecting to mobile networks, making phone calls, and sending/receiving SMS messages. [1][2]
The baseband firmware resides on the same storage (eMMC) as the Android operating system but runs independently on a separate baseband processor. It communicates with the Android OS through shared memory and AT commands. [3][4]
Baseband versions are different from Android build numbers. The baseband version refers specifically to the firmware running the cellular radio hardware. [5]
Baseband firmware has been found to contain vulnerabilities that could allow remote command execution if exploited. However, Android devices from reputable manufacturers like Google/Pixel generally receive frequent baseband updates to address such issues. [6][7][8]"
[1] https://www.quora.com/What-do-baseband-version-and-kernel-ve...
[2] https://www.reddit.com/r/AndroidQuestions/comments/1wzmp7/wh...
[3] https://android.stackexchange.com/questions/219230/where-is-...
[4] https://stackoverflow.com/questions/24569075/how-mobile-os-t...
[5] https://forums.androidcentral.com/threads/difference-between...
[6] https://techcrunch.com/2019/11/08/android-baseband-flaws/
[7] https://www.reddit.com/r/GrapheneOS/comments/11op7yz/remote_...
[8] https://news.ycombinator.com/item?id=38616922
And the last link is this hackernews post!