Currently, TimeZone treat the tzID case sensitive. But in ECMAScript tzID is case insensitive. This make the v8 implementation clumsy and not efficient and have to have special case. Could we make the ICU tzID also case insensitive? That will speed up v8 implementation and reduce special case handling
I suspect TZ Database maintainer define zone syntax case in-sensitive. I think we want to check this in the tz mailing list. I'll read the spec and post a question first.