Scripts

and in which ones exactly?

Here, take a look:
TalkBoxForPlayers (PLAYER_1, face_Derin, bio_Derin, nil, nil, 'TALK', 0, name_Derin, GetMapDataPath().."names_and_desc/q000.txt", 1, GetMapDataPath().."dialogs/derin001.txt");

PLAYER_1 - indicates which player the message is shown to
face_Derin - variable - this is the icon texture
bio_Derin - variable, text that appears when you right-click the icon
'TALK' - function (here it selects the answer number)
0 or 1 - window type ("ok" or "ok/close")
name_Derin - variable, text at the very top of the window
GetMap.... - here it's the path to the file (by default, it writes 'your choice')
1...5 or nil - the number of the highlighted answer
then come the paths to files from 1 to 5 (in the example, only 1)

(the path of the Fallen or the death of the Raven - it's used in both cases, it's not difficult to figure out)
And also - the function is non-modal, all variables are the path to specific files

Added 6 minutes later
Here's another one, you might not know, in MapScriptEditor, when you type a function and put the first parenthesis '(', a hint appears - it's conveniently done, and in principle, the same thing I described will pop up