These files need to be deployed into your Android source code directory to ensure build.prop file on the device contains the correct URL for receiving OTA updates.  This is to point the updated app at the OTA server you're hosting.

1. Create the directory lineage/vendor/extra
2. Review and edit the contents of file product.prop to ensure the URL is what you want your device pointed to.
3. Place the product.mk and product.prop files in this directory

The files will then be automatically read by the build system and patch build.prop with the updated URL.