Categorization of results based on how likely they are to
represent a match, based on the number of elements they contain
which imply a match.
Values:
LIKELIHOOD_UNSPECIFIED (0):
Default value; same as POSSIBLE.
VERY_UNLIKELY (1):
Few matching elements.
UNLIKELY (2):
No description available.
POSSIBLE (3):
Some matching elements.
LIKELY (4):
No description available.
VERY_LIKELY (5):
Many matching elements.
