XSLT Metrics ( http://code.menteithconsulting.com/wiki/XSLTMetrics), by Tony Graham, is a stylesheet for some descriptive, rather than prescriptive or proscriptive, metrics about what's in a stylesheet. The purpose of the metrics is finding out what's in a stylesheet rather than telling you how to write your stylesheet.
The metrics stylesheet is written in XSLT 1.0 so it usable by the maximum number of people.
Current sample output from the DocBook XSLT stylesheets:
Stylesheets: 61 With comments: 54 Both preceding and containing comments: 0 Preceding comments only: 0 Containing comments only: 0 Templates: 1833 With comments: 446 Both preceding and containing comments: 56 Preceding comments only: 151 Containing comments only: 239 Named templates: 421 Recursive: 0 Moded templates: 933 Named moded templates: 2 Imports: 3 Includes: 57