google chrome – What does double dash (–) implies in Selenium ChromeOptions

As per Command-Line Options:

Unix tradition encourages the use of command-line switches to control
programs, so that options can be specified from scripts. There are
three conventions to distinguish command-line options from ordinary
arguments as follows:

• The original Unix style
• The GNU style
• The X toolkit style

The GNU style uses option keywords (rather than keyword letters)
preceded by two hyphens. It evolved years later when some of the
rather elaborate GNU utilities began to run out of single-letter
option keys (this constituted a patch for the symptom, not a cure for
the underlying disease). It remains popular because GNU options are
easier to read than the alphabet soup of older styles. GNU-style
options cannot be ganged together without separating whitespace.

The GNU double-hyphen option leader was chosen so that traditional single-letter options and GNU-style keyword options could be unambiguously mixed on the same command line.