These report template variables can be used in the "reports" template:

{REPORTTYPE} - Contains "topic" for topic reports, "post" for post reports.
{REPORTREASON} - The reason the reporter gave for reporting.
{REPORTDATE} - The date and time that the report was made.
{REPORTRESOLVED} - True if the report has been resolved by a moderator, or false if it hasn't. For use in conditionals.
{REPORTACTION} - The action taken to resolve the report (if resolved).
{REPORTMODERATORPROFILEURL} - The profile URL of the moderator who resolved the report.
{REPORTMODERATORNAME} - The name of the moderator who resolved the report.
{REPORTDISCUSSIONURL} - If you've selected at Admin Panel -> Settings -> General to send report to a special forum in WSN Forum, this is the forum thread URL where the report is being discussed.
{REPORTDISCUSSIONREPLIES} - If you've selected at Admin Panel -> Settings -> General to send report to a special forum in WSN Forum, this is the number of replies to the forum thread where the report is being discussed.
{REPORTDISCUSSIONLASTPROFILEURL} - If you've selected at Admin Panel -> Settings -> General to send report to a special forum in WSN Forum, this is the profile url of the last poster in the forum thread where the report is being discussed.
{REPORTDISCUSSIONLASTPOSTERNAME} - If you've selected at Admin Panel -> Settings -> General to send report to a special forum in WSN Forum, this is the name of the last poster in the forum thread where the report is being discussed.
{REPORTDISCUSSIONLASTPOSTURL} - If you've selected at Admin Panel -> Settings -> General to send report to a special forum in WSN Forum, this is the url link to the last post of the forum thread where the report is being discussed.

These template vars can be used in the language item email_reportlinkbody, which is the body text emailed to the site admins for topic reports if you've selected to email reports:

{COMMENT} - The explanation written by the reporter.
{PROBLEMTYPE} - The type of problem, as chosen from the selector on the report page.
All {LINK variables will show the appropriate values of the topic which has been reported.
All {CAT variables will show the appropriate values of the forum of the topic which has been reported.
All {MEMBER variables will show the appropriate values of the member who reported the topic.

These template vars can be used in the language item email_reportpostbody, which is the body text emailed to the site admins for post reports if you've selected to email reports:

{COMMENT} - The explanation written by the reporter.
{PROBLEMTYPE} - The type of problem, as chosen from the selector on the report page.
All {COMMENT variables will show the appropriate values of the post which has been reported.
All {LINK variables will show the appropriate values of the topic which reported post is associated with.
All {CAT variables will show the appropriate values of the forum of the post which has been reported.
All {MEMBER variables will show the appropriate values of the member who reported the post.