This procedure is defined in the server but not documented via ad_proc or proc_doc and may be intended as a private interface.
The procedure is defined as:
proc mime::reversemapencoding {mimeType} {
variable reversemap
set lmimeType [string tolower $mimeType]
if {[info exists reversemap($lmimeType)]} {
return $reversemap($lmimeType)
}
return {}
}