mathbb-one is distributed under two sets of terms.

tex/mathbb-one.sty, doc/ and source/
  Copyright (C) 2026 Thomas Beck.
  May be distributed and/or modified under the conditions of the LaTeX Project
  Public License, version 1.3c or later: https://www.latex-project.org/lppl.txt

type1/, tfm/, map/ and opentype/ (the mathbb-one fonts)
  Derived from the bbm Metafont sources by Gilles F. Robert (1993), which carry
  the notice:

    You may freely use, modify and/or distribute this file.

  The mathbb-one fonts are distributed under the same terms.