The phone numbers matched exactly. Two phone number strings are an exact match if the country code, national phone number, presence of a leading zero for Italian numbers and any extension present are the same.
The national phone number matched. Two phone number strings match at this strength if either or both has no region specified, and the national phone number and extensions are the same.
The phone numbers did not match.
The weakest sort of match. Two phone numbers match at this strength if either or both has no region specified, or the region specified is the same, and one national phone number could be a shorter version of the other number. This includes the case where one has an extension specified, and the other does not.
The strength of a phone number match.