versionSort :: [String] -> [String]

versionSort = sortOn brkND

  where

    tr f g (x,y) = f x : g y

    -- ND for non-digits

    brkND = tr Right brkD . span (not . isDigit)

    brkD = tr (Left . read @Int) brkND . span isDigit

(side question: does the helper function tr I defined above have a commonly known name?)

I don't think so, but that's just because you made the cut at a weird point. It's very close to (***) from Control.Arrow, Data.Tuple.Extra, Data.Profunctor, and other libraries, also known as bimap in Data.Bifunctor and in the lens package.

Rewriting your functions to tease it out even more (not tested):

    versionSort :: [String] -> [String]
    versionSort = sortOn gatherNonDigits
      where

        gatherAll predicate gather continue = uncurry (:) . (gather *** continue) . span predicate

        -- 'NonDigits' for non-digits
        gatherNonDigits = gatherAll (not . isDigit) wrapNonDigits gatherDigits
        gatherDigits    = gatherAll        isDigit  wrapDigits    gatherNonDigits

        wrapNonDigits   = Right
        wrapDigits      = Left . read @Int