Passing privilege is a relative state of privilege with respect to an oppressed group that you are part of, but are able to distance yourself from due to your proximity to the dominant group in terms of appearance.
The core fallacy of 'passing' is that by developing enough of an exterior facade of belonging, one can escape oppressive social structures through camouflage.
The fact is, that even if 'passing' can allow a person to appear to not be a member of the marginalised group - they will never be fully accepted as a member of the privileged group.
The simple reason is linguistics. The encoded communication structures that are embedded in the language of the privileged group can never be learned to the level of a native speaker, because a native speaker is instinctive in the language.
Whether that language be the language of anglocentrism, cisheteropatriarchy or class. "Passing" is only conditional on the ability to facilitate and normalise the continuation of the norms that perpetuate the supremacy of the privileged group. "Passing privilege" is a conditional privilege whose core condition is that you accept your own subjugation within the structures of the 'privilege' you receive.
If you are a foreigner in a colonialist nation, then you understand this well.
Whether you learn the language fluently or not, you are never fully accepted into the society, because your 'tells' are too obvious. Any visible shreds of your own native culture are seen as abnormalities and you are 'othered' rather than accepted. Whether it's your inability to grasp local slang, or sarcastic humour, or obliviousness to the 'common sense' of the local people, you are seen as an 'other' for non-conformity.
(...) (White-passing privilege)
This is different to cis-passing privilege which relates to the ability to perform your assigned-gender with sufficient skill to pass as said assigned-gender (pre-transition) 'or' (post-transition) to physically alter one's body, clothing and mannerisms to a point that you are socially 'read' as a cisgender member of the "opposite sex" (as opposed to a passably-transitioned transgender member of the associated gender group[CP 1]).
For some transgender people this is possible within the social norms of their culture: i.e. cultures that encourage gender diversity within the gender binary (where boys can dance and sing, and women can learn a trade and participate in all social events)
Transgender people have varying degrees of 'cis-passing privilege' depending on this, and for many transgender people the only option is to pursue transition in order to align our physical bodies with the social expectations of our gender.
Non-binary transgender people often struggle, regardless of transition because there is no physical body that directly correlates with a socially-encoded set of gender norms to which we ourselves correlate. Our gender doesn't fit into the neat social expectations of 'woman' or 'man' - perhaps some of both or perhaps little/none of either.
- e.g. "men", "women", "boys", "girls", "ladies", "gentlemen", "butches", "femmes", "queens", "studs", "bears", "twinks", etc.
Transwomen who are perceived as male do not have male privilege. Male privilege benefits males.
However, transmen do not fully access male privilege until they transition, which indicates that 'access' to privilege is integral to the passing privilege debate.
Transwomen and transfeminine people can receive misdirected access to male privilege due to being misgendered as male. This is not the same as having male privilege, true access to male privilege is only afforded to people who can conform to cisheteromasculine ideals, access to male privilege is given in proportion to this conformity and transfeminine people tend to only be able to conform to these pressures under the extreme duress of transmisogyny.