When searching the help for count, :h count I'm shown the help page:                            *count* *[count]*[count] An optional number that may precede the command to multiply        or iterate the command.  If no number is given, a count of one        is used, unless otherwise noted.  Note that in this manual the        [count] is not mentioned in the description of the command,        but only in the explanation.  This was done to make the        commands easier to look up.  If the 'showcmd' option is on,        the (partially) entered count is shown at the bottom of the        window.  You can use <Del> to erase the last digit (|N<Del>|).I'm curious, what is the notation *count* *[count]* telling me?More specifically:What is the significance of the asterisk *?What do the lack or presence of brackets [] mean?
What does `*foo* *[foo]*` mean in the vim help system?
help system
The meaning of the * (or more specifically *word*) is, that this defines a help tag you can jump to. So if you enter :h count Vim knows where to get you to have you read about the count. This also matters for completion and highlighting (by default the * will be concealed so it won't be visible). If you write a help document and you want to reference such a word, it is written within |word| so that you can put your cursor on word and press CTRL] and Vim will jump to the definition of the word.I believe the notation [word] is just a denotion for the word being optionally for certain commands, e.g. look at :h J and see how it talks about [count] (if it is not given a default of 1 is being assumed (except for joining lines where a default of 2 is used)).