[Reverence]

Code:

for %%a in (%a%,%b%,%c%) do ( echo texttexttext>%%a )

so %%a is not refer to 'a' variable we've set up? and the contain of %%a is defined within 'do' block?

The "in" specifies the the string that we are setting the variable "%%a" too

what's that supposed to mean?

I don't get your first question.

The second question, though, means that what is inside the parentheses after the "in" defines "%%a".