org-plain-time-of-day-regexp

org-plain-time-of-day-regexp is a variable defined in `org.el'.
Its value is

"\\(\\<[012]?[0-9]\\(\\(:\\([0-5][0-9]\\([AaPp][Mm]\\)?\\)\\)\\|\\([AaPp][Mm]\\)\\)\\>\\)\\(--?\\(\\<[012]?[0-9]\\(\\(:\\([0-5][0-9]\\([AaPp][Mm]\\)?\\)\\)\\|\\([AaPp][Mm]\\)\\)\\>\\)\\)?"

• This variable may be risky if used as a file-local variable.

Documentation:
Regular expression to match a plain time or time range.
Examples: 11:45 or 8am-13:15 or 2:45-2:45pm. After a match, the following
groups carry important information:
0 the full match
1 the first time, range or not
8 the second time, if it is a range.