Canon EOS R6 Advanced User's Manual page 339

Movie Recording Count
You can select how time is displayed on the movie recording screen.
Rec time
During recording standby, displays the available recording time. During recording,
displays the time that has elapsed since movie recording began (1).
Time code
Displays the time code during movie recording (2).
Caution
Display of the available recording time may change during recording standby.
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