After a long time struggling with this, the solution accidentaly came today 😀
I’m coding via GNU screen in urxvtc terminal.
To copy/paste selected text I pressed down Ctrl + Mouse Right Click and the following context menu shows up:
The Ctrl + Mouse Middle Click shows the following context menu:
Helpful alternatives at https://stackoverflow.com/questions/16111548/how-copy-the-gnu-screen-copy-buffer-to-clipboard
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