NewPP parser report/en

NewPP is an abbreviation for "New PreProcessor" (new at the time of Tim Starling's 2008 parser rewrite for MediaWiki 1.12, that is). One is most likely to find it at the bottom of the HTML source of wiki pages, referring to the preprocessor report that contains statistics on what resources were used to render the page, and usage of various parsing-related quotas (such as number of expensive calls, or number of preprocessor tree nodes).

On a Wikimedia site it will look something like this:

followed by a per-template expansion time report and a debug message with the parser cache key.

It will also be available as the JavaScript configuration variable, and displayed in edit preview mode under the edit window (as a dropdown under the name "Parser profiling data") when using the wikitext editor.

See w:Wikipedia:Template limits for details on what the lines mean.