non-functional jbrowse regex track

gistfile1.txt

{
    "label" : "SpCas9 NGG PAM sites",
    "unsafeMouseover" : true,
    "unsafePopup" : true,
    "type":"CanvasFeatures",
    "category" : "1testing",
    "key" : "SpCas9 NGG PAM sites",
    "metadata" : {
       "shortInfo" : "Streptococcus pyogenes Cas9 PAM sites based on NGG motif."
    },
    "storeClass" : "RegexSequenceSearch/Store/SeqFeature/RegexSearch",
    "searchParams" :[{"expr":".GG"}]
}