Report format aliases should use the IssuesAliasConstants.MainCakeAliasCategory and ReportingAliasConstants.ReportingFormatCakeAliasCategory constants for defining their category:
[CakeAliasCategory(IssuesAliasConstants.MainCakeAliasCategory)]
public static class MyReportFormatAliases
{
[CakeMethodAlias]
[CakeAliasCategory(ReportingAliasConstants.ReportingFormatCakeAliasCategory)]
public static IIssueReportFormat MyReportFormat(
this ICakeContext context)
{
}
}