@preformatted tag is the analogy of HTML <pre> tag. Text inside @preformatted tag will be copied to documentation, preserving all whitespaces and newlines and using fixed-width font.
This means that usual rules of pasdoc do not apply within @preformatted. Within @preformatted tag amount of whitespace does matter, empty line is not converted to new paragraph, @-tags are not expanded etc.
Example:
1 { Here's something for those "Star Wars" freaks
2 (from [http://www.chris.com/ascii/index.html],
3 with ")" replaced by ">"):
4
5 @preformatted(
6 ________________. ___ .______
7 / | / \ | _ \
8 | (-----| |----`/ ^ \ | |_> |
9 \ \ | | / /_\ \ | /
10 .-----> | | | / _____ \ | |\ \-------.
11 |________/ |__| /__/ \__\| _| `.________|
12 ____ __ ____ ___ .______ ________.
13 \ \ / \ / / / \ | _ \ / |
14 \ \/ \/ / / ^ \ | |_> || (-----`
15 \ / / /_\ \ | / \ \
16 \ /\ / / _____ \ | |\ \---> |
17 \__/ \__/ /__/ \__\|__| `._______/
18 )
Sorry, but now that TableTags are implemented, I can't imagine a better example for @preformatted tag