A wall-clock date without a zone does not identify one global instant. EpochLens requires Z or ±HH:mm and never guesses from the browser zone.
Z names UTC
A trailing Z means zero offset from UTC. It is the clearest form for logs and machine fixtures when a local civil time is not required.
Numeric offsets identify the instant
2024-01-01T01:30:00+01:30 is the same instant as 2024-01-01T00:00:00Z. EpochLens subtracts the stated offset exactly.
An offset is not a time-zone history
A fixed offset identifies this instant but does not encode daylight-saving rules for another date. Use a named-zone tool when that is the actual job.