The story
From / + abbreviation of nobody here, using the tone indicator format of slash-prefixing set by the earlier /s (“sarcasm”), though it does not indicate tone, instead giving informational context.
Etymology from Wiktionary, CC BY-SA 4.0.
/nbh
Today it means: Denotes that the preceding statement is not directed at the participants of the discussion or the followers of the author. Full definition →