Hi, below follows some notes about current documentation issues.
We currently use the v3.0.x; but, probably, some notes are actual for other versions also (3.2, 3.4).

1. Section "What's new in Zabbix 3.0.12" has the sentence:

Zabbix 3.0.12 is not released yet.

However, it is not a truth: this version was released; moreover – the next version (3.0.13) is released already.

2. Section about remote command execution tells:

Remote commands are limited to 255 characters. Multiple commands can be executed one after another by placing them on a new line. Remote commands may contain macros.

However, it is not clear: this limitation (255 chars) is before the macros substitution or thereafter? It's needed a clarification here.

3. The same question about notification actions and custom alertscripts: are there some limitations on the size and/or character set to parameters (for subject and body of message, for alertscript parameters), both before and after macros substitution? For example: is it possible to transfer a multi-lined string as a "Subject" field to the custom alertscript?

4. The list of macros page was in a table format up to v2.4. Since v3.0 this format was changed – probably, due to its width. However, some content becomes more hard for searching and/or understanding.
Examples:
4.1. There was a column named "Trigger-based notifications and commands". We could look at this column and see all macros available for this use-case. The only way available now is to perform a searching in the browser. Moreover, if we search the same string "Trigger-based notifications and commands", we could not find, for example, the {EVENT.DATE} and {EVENT.ID} macro's: they labelled as "Notifications and commands" (without a "Trigger-based" substring).
4.2. Just opposite case: macro's {EVENT.RECOVERY.*} have labels "Trigger-based notifications and commands"; however, they are don't work in any commands (they works in trigger-based notifications only).

5. It is not clear the difference between {EVENT.ID} and {EVENT.VALUE} macro. The short explanation or example would be enough, something like:

{EVENT.ID} Internal unique numeric ID of the event that triggered an action.

{EVENT.VALUE} Numeric value of the event that triggered an action (zero for problem, 1 for recovering).

Thanks!