Android system NFC framework introduction and develop guide
It also describes which TNFs cannot be mapped to a MIME type or URI. In these cases, the tag dispatch system falls back to ACTION_TECH_DISCOVERED.
For example, if the tag dispatch system encounters a record of type TNF_ABSOLUTE_URI, it maps the variable length type field of that record into a URI. The tag dispatch system
encapsulates that URI in the data field of an ACTION_NDEF_DISCOVERED intent along with other information about the tag, such as the payload. On the other hand, if it encounters a record of type TNF_UNKNOWN, it creates an intent that encapsulates the tag's technologies instead.
Table 1. Supported TNFs and their mappings
Table 2. Supported RTDs for TNF_WELL_KNOWN
and their mappings