GMT — Greenwich Mean Time
GMT is Greenwich Mean Time, +00:00, used in Europe / Africa. In code, use Etc/GMT rather than the abbreviation.
Use the IANA name, not the abbreviation
Python
from datetime import datetime
from zoneinfo import ZoneInfo
# right: an IANA zone carries the full history of rule changes
now = datetime.now(ZoneInfo("Etc/GMT"))
print(now.isoformat(), now.tzname())
# wrong: an abbreviation is not resolvable, and a hard-coded offset
# silently rots the next time the rules change
# now = datetime.now(timezone(timedelta(hours=...))) # don'tGMT questions
What does GMT stand for?
GMT is Greenwich Mean Time, +00:00, used in Europe / Africa. The IANA zone to use in code is Etc/GMT.
What time is it in GMT right now?
Greenwich Mean Time: 00:15 on Thursday (GMT).
Which IANA timezone should I use instead of GMT?
Etc/GMT for Greenwich Mean Time. Date libraries cannot resolve bare abbreviations, and an abbreviation carries no daylight-saving history, so a stored offset silently rots when a government changes the rules.