LaTeX Beamer: How do I see a list of all supported special frames of a theme?

How do I see a list of all supported special frames of a theme, say, Berlin?

PS: This question was prompted by this answer:

Another approach could be to use a theme which provides a special frame for this, e.g. with the metropolis theme, one can simply do

\documentclass{beamer}

\usetheme{metropolis}

\begin{document}
    
\begin{frame}
normal frame
\end{frame}

\begin{frame}[standout]
Thanks
\end{frame} 
    
\end{document}

The Berlin theme is one of the themes provided by beamer. You can see a list of its frame options in the beamer user guide, section "8.1 The Frame Environment":

• allowdisplaybreaks
• allowframebreaks
• b
• c
• t
• s
• noframenumbering
• fragile
• environment
• label
• plain
• shrink
• squeeze

Third party themes may define additional frame options, consult their respective documentations or search their source code for \define@key{beamerframe}{.