Which blackboard font is used?

Question

Can anyone help me in knowing which mathbb font is being used here and how to use it?

Thanks!

Answer 1

Those two : Q and Z look like those from the dsfont package with the sans option.

\documentclass[12pt, border=2pt]{standalone}
\usepackage[sans]{dsfont}
\begin{document}
$\mathds{ZQ}$
\end{document}