In the example below (when changed to beamer mode) there is a frame with two slides. On the first slide the text "Text 1" is shown in red color. On the second slide it is shown in blue color (default).
\documentclass[10pt,t,handout]{beamer}
\usepackage[english]{babel}
\begin{document}
\begin{frame}<handout:2>
{\color<1>{red}Text 1}
{\color<2>{green}Text 2}
\end{frame}
\end{document}
For the creation of handouts, however, I have added an overlay specification to the frame environment to only include slide 2 in the handouts. I would assume that the generated slide in the handout would have "Text 1" in blue and "Text 2" in green.
Surprisingly for me the result in the handout is a slide where "Text 1" is red and "Text 2" is green. This brought me to my question: What is the meaning of an overlay specification for handout mode that is added to a frame environment?
Please note: I already found a workaround, namely to provide individual overlay specifications for handout mode to the \color command for "Text 1":
{\color<1| handout:0>{red}Text 1}
That is, I am not asking to figure out how to make it work - I rather want to understand the background.
Update: Although I had searched SE before, only after submitting I was pointed towards this question: Can I declare a different overlay specification in different beamer modes?. The background is, that the line
{\color<1>{red}Text 1}
actually means
{\color<1| handout:1->{red}Text 1}
Thus, if I change the line to
{\color<all:1>{red}Text 1}
then the handout is generated as I had expected.