New statistic tossedPacketsEnergy in JVB breaks prometheus-json-exporter

I’m using prometheus-json-exporter to get statistics off the videobridges. prometheus-json-exporter “fetches arbitrary JSON from remote API and exports the values as gauge metrics”. Example usage:
curl -s http://jvb-host:9116/probe?target=http://localhost:8080/colibri/stats

This worked nicely until I upgraded to the latest stable (jitsi-videobridge2 version 2.1-538-g062e9f56-1). Statistics contain the new

"tossedPacketsEnergy":{"average":null,"max":0,"total_value":0,"total_count":0,"buckets":{"<= 7":0,"<= 15":0,"<= 23":0,"<= 31":0,"<= 39":0,"<= 47":0,"<= 55":0,"<= 63":0,"<= 71":0,"<= 79":0,"<= 87":0,"<= 95":0,"<= 103":0,"<= 111":0,"<= 119":0,"> 119":0,"p99<=":-1,"p999<=":-1}},

that causes prometheus-json-exporter to panic:

descriptor Desc{fqName: "tossedPacketsEnergy::buckets::<= 31", help: "Retrieved value", constLabels: {}, variableLabels: []} is invalid: "tossedPacketsEnergy::buckets::<= 31" is not a valid metric name

I suspect that “<,=,>,space” are the problem. According to the docs the metric name “may contain ASCII letters and digits, as well as underscores and colons”.

Any chance that tossedPacketsEnergy could be reported in a way compatible with prometheus-json-exporter? Otherwise I’d have to redesign monitoring which I’d prefer not to.

Cheers, Dieter

PS.: If this is not the right place to ask please tell me where