This character is a Other Symbol and is commonly used, that is, in no specific script. The character is also known as motor sports.
The glyph is not a composition. Its East Asian Width is wide. In bidirectional text it acts as Other Neutral. When changing direction it is not mirrored. U+1F3C1 offers a line break opportunity at its position, except in some numeric contexts.
The CLDR project calls this character “chequered flag” for use in screen reading software. It assigns these additional labels, e.g. for search in emoji pickers: checkered, chequered, finish, flag, flags, game, race, racing, sport, win.
This character is designated as an emoji. It will be rendered as colorful emoji on conforming platforms. To reduce it to a monochrome character, you can combine it with Variation Selector-15: 🏁︎ See the Emojipedia for more details on this character’s emoji properties.
The Wikipedia has the following information about this codepoint:
Racing flags are traditionally used in auto racing and similar motorsports to indicate track conditions and to communicate important messages to drivers. Typically, the starter, sometimes the grand marshal of a race, waves the flags atop a flag stand near the start-finish line. Track marshals are also stationed at observation posts along the race track in order to communicate both local and course-wide conditions to drivers. Alternatively, some race tracks employ lights to supplement the primary flag at the start-finish line.