Hi Andreas

 > I think the documentation of \prop_get:NN in l3prop is wrong.
 > It says that <info> of \prop_get:NN is assigned to a <tlp>,
 > but actually it is assigned to a <toks>.
 > The same applies to \prop_get_gdel:NNN.

well spotted, but I fear it is not the documentation but rather the
implementation that is incorrect right now.

in the past that was

\def_long:Npn \prop_get_aux:w #1#2#3#4{\tlp_set_eq:NN#4#2}

and xpackages like xmarks use it with tlps

will investigate