Echo the expression(s) as a true message, saving the message in the |message-history|. Spaces are placed between the arguments as with the :echo command. But unprintable characters are displayed, not interpreted. The parsing works slightly different from :echo, more like :execute. All the expressions are first evaluated and concatenated before echoing anything. If expressions does not evaluate to a Number or String, string() is used to turn it into a string. Uses the highlighting set by the :echohl command.

Like |:echomsg| but when the messages popup window is available the message is displayed there. This means it will show for three seconds and avoid a |hit-enter| prompt. If you want to hide it before that, press Esc in Normal mode (when it would otherwise beep). If it disappears too soon you can use :messages to see the text. When [N] is given then the window will show up for this number of seconds. The last :echowindow with a count matters, it is used once only. The message window is available when Vim was compiled with the +timer and the +popupwin features.