How to create the config-5.10 file in target/xxx directory?

Hi, everyone, I need to add a new target, I find that there is a config-5.10 files under all the other targets. Where does this file come from and what is the relationship with the config file under target/generic ? Can someone give me a help? Thanks!

root@d33cdc59f198:/home/openwrt/target/linux/bcm4908# tree -L 1
.
|-- Makefile
|-- base-files
|-- config-5.10
|-- files-5.10
|-- generic
|-- image
`-- patches-5.10
root@d33cdc59f198:/home/openwrt/target/linux/generic# tree -L 1
.
|-- PATCHES
|-- backport-5.10
|-- config-5.10
|-- config-filter
|-- files
|-- hack-5.10
|-- image
|-- other-files
`-- pending-5.10

6 directories, 3 files
type or paste code here

The target/generic is used as the global defaults, and then the target specific config can incrementally modify it for those items that need changing for the target. (And some config symbols only exist for some targets.)

The origins of each targets changes are likely in CPU docs/specs, GPL code for OEM manufacturers using that chip for the router being the first in a new target etc.

Thanks, and are there any guides or examples ?

There's a big part of the wiki dedicated to it: