[tz] Reason for removal of several TZ

Hi guys, Almost a year ago, commit 2999bb5bee719acbba8b9dd50fb9fb00c7788623 removed several TZ abbreviations and I'm trying to understand this. For my own use, what I'm after is WGT/WGST which are now "simply -03". WGT/WGST has been in tzdata for a long time, so the removal causes certain things to go belly up. The change was only implemented in Ubuntu recently, which is why this only turned into a problem for me now. WGT/WGST seems to be a widely accepted abbreviation for the West Greenland Time zone. So can someone explain to me the reason behind the removal and what would needed to get it re-implemented? Thanks. /Thomas