[enhancement]: metadata injection through kernel paramaters

Hi,

Let me apologize whether this topic has been already somewhere discussed or maybe even documented. I haven't found any lead, thus I am asking you this way.

Using the kernel parameter ``cc: end_cc`` user can inject any user-data that can be used for an instance. I have noticed that the `` will land under `merged_cfg` key when querying the data structure.

I am trying to use a templated user-data for my testing instance (no cloud environment) that has a short lifespan. The user-data is stored in a secondary image (qcow2) and contain some variables I need to change accordingly for a single run of the instance e.g. package version, build number or registration code.

Is there a way that I can inject this information at the boot time among kernel parameters, and they would land under a different key (v1, vendordata, etc) rather than in `merged_cfg`?

Thanks and sorry for the noise if this has been somewhere else clarified.