\documentclass{article}
\usepackage[ngerman]{babel}
\usepackage{biblatex}
\bibliography{biblatex-examples.bib}
\usepackage{regexpatch}
\makeatletter
\tracingxpatches
\xpatchbibdriver{incollection}{%
  \tralalala{\labelnamepunct}\newblock
}{%
  \setunit{\addcolon}\newblock
}{}{}
\makeatother

\begin{document}
\fullcite{brandt}
\end{document}

    455 \NewDocumentCommand{\xpatchbibdriver} { s +m +m +m +m +m }
    456  {
    457   \IfBooleanTF{#1}
    458    { \exp_args:Nc \xpatch_patchcmd_all:Nnnnn {blx@bbx@#2} {#3}{#4}{#5}{#6} }
    459    { \exp_args:Nc \xpatch_patchcmd_once:Nnnnn {blx@bbx@#2} {#3}{#4}{#5}{#6} }
    460  }
    461 \NewDocumentCommand{\regexpatchbibdriver} { s +m +m +m +m +m }
    462  {
    463   \IfBooleanTF{#1}
    464    { \exp_args:Nc \xpatch_regexpatchcmd_all:Nnnnn {blx@bbx@#2} {#3}{#4}{#5}{#6} }
    465    { \exp_args:Nc \xpatch_regexpatchcmd_once:Nnnnn {blx@bbx@#2} {#3}{#4}{#5}{#6} }