10 LF (Line Feed). A format effector that advances the active position to the same character position on the next line. (Also applicable to display devices.) Where appropriate, this character may have the meaning “New Line” (NL), a format effector that advances the active position to the first character position on the next line. Use of the NL convention requires agreement between sender and recipient of data.
ASCII 1968 - https://www.rfc-editor.org/info/rfc20
ASCII 1977 - https://nvlpubs.nist.gov/nistpubs/Legacy/FIPS/fipspub1-2-197...
The second sentence is the UNIX interpretation of LF doing the equivalent of CRLF. But calling it a standard line ending when it's an alternative meaning defined in the standard as "requires agreement between sender and recipient of data" is a bit of a stretch. It's permissible by the standard, but it's not the default as per the standard