Basically imagine the word tone applied to the community, also encompassing a lot more of the non-content parts. So not just the tone of the discussions, but a

Basically imagine the word tone applied to the community, also encompassing a lot more of the non-content parts. So not just the tone of the discussions, but also the way questions are asked, how new people to communities are treated, the length and style of response and discourse. People basically use it to say "the tone++ of the discussion" to badly abuse a programming metaphor.