That is an example of using format lists with the PUT statement. Syntax is list of variables in () followed by list of formats in another set of (). If the list of formats is too short it cycles.
The = means print the name of the variable followed by equal sign and the value. The / means start a new row. So the result is you get 10 lines in the log that look like:
date1=....
date2=....
....
date10=...