One of the prerequisites that a Fiori UI could be extensible is that it should have a corresponding business context registered in tcode SCFD_REGISTRY:

For research purpose, we can get a list of all available business context and save it locally via a Batch request in postman:

Content type: multipart/mixed;boundary=batch_19f5-6916-f298

x-csrf-token: you should generate it dynamically

request body:

--batch_19f5-6916-f298

Content-Type: application/http

Content-Transfer-Encoding: binary

GET BusinessContextSet?$skip=0&$top=500&$inlinecount=allpages&$orderby=BusinessContextDescription%20asc HTTP/1.1

Accept-Language: en

Accept: application/json

MaxDataServiceVersion: 2.0

DataServiceVersion: 2.0

--batch_19f5-6916-f298--

an example of response got from QJ3/500:

the business context for MARA: