docs(akmods): Add note about extra akmods which use different COPR repo

modules/akmods/README.md

@@ -22,6 +22,8 @@ See available tags here: https://github.com/ublue-os/akmods/#how-its-organized
 
 ## Known issues
 
+### Outdated akmods compared to the kernel version fail the build
+
 When the upstream base image is failing to build for some time, you will probably notice that this module fails too with this error:
 ```
 Resolving dependencies...done
@@ -32,3 +34,20 @@ Problem: package "version_of_akmod" from @commandline requires "version_of_kerne
 
 Just wait for the base image build to resolve & akmods module will start working again.
 If this issue happens for a prolonged period of time, report it to the upstream repo if not already reported or worked on.
+
+### Some akmods are not installing due to lack of some additional akmod package
+
+Example of the error:
+```
+Resolving dependencies...done
+error: Could not depsolve transaction; 1 problem detected:
+Problem: conflicting requests
+- nothing provides kvmfr-kmod-common >= 0.0.git.21.ba370a9b needed by kmod-kvmfr-6.9.4-200.fc40.x86_64-0.0.git.21.ba370a9b-1.fc40.x86_64 from @commandline
+```
+
+This happens when the mentioned akmod is not pulled from ublue-os/akmods COPR repo, but from some other one.  
+Those akmods are rare & they are residing in `extra` akmods stream.  
+There is also the information of repo source of the akmod, where you can see which akmod is the "exotic" one.  
+All this information can be seen in [`akmods` repo](https://github.com/ublue-os/akmods).
+
+The solution to this problem is to add the affected akmod repo to [`rpm-ostree`](https://blue-build.org/reference/modules/rpm-ostree/) module in `repos` section.