Ambiguous statement about Unicode characters input with their code points
The documentation about inserting any Unicode characters with their code points is ambiguous. The moments and options to hold and release each key is not clear. There are 2 possibilities that work in some environments, so the documentation ambiguity may not even be noticed. But one of these 2 possibilities will not work in all environments.
The current documentation seems to ask to hold the U key all the time, since it is written with a "+" (plus sign) as Ctrl and Shift keys are. Typing other keys while holding these 3 keys will not work in several keyboards I know.
If we type u (releasing it), and release Ctrl and Shift keys, before typing the 4 character codes of the desired Unicode character, we will need to type Space or Enter keys to make the character appear, substituting what we typed and is shown.
If we type u (releasing it), never release both Ctrl and Shift keys, type the 4 character codes of the desired Unicode character, the desired character will appear at the moment we release Ctrl and Shift keys, substituting what we typed and is shown, just like the previous way to do this operation.
The ambiguity exists also in the Portuguese translation of the documentation, which is the one shown to me, when I visit:
https://help.gnome.org/users/gnome-help/stable/tips-specialchars.html
It may be the case in several other languages.