Double RFC prefix:
$ grep -r 'RFC [0-9][0-9]*: RFC' open/src
open/src/java.compiler/share/classes/javax/tools/JavaFileManager.java: * @spec https://www.rfc-editor.org/info/rfc3986 RFC 3986: RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
open/src/java.compiler/share/classes/javax/annotation/processing/Filer.java: * @spec https://www.rfc-editor.org/info/rfc3986 RFC 3986: RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
$ grep -r 'RFC [0-9][0-9]*: RFC' open/src
open/src/java.compiler/share/classes/javax/tools/JavaFileManager.java: * @spec https://www.rfc-editor.org/info/rfc3986 RFC 3986: RFC 3986: Uniform Resource Identifier (URI): Generic Syntax
open/src/java.compiler/share/classes/javax/annotation/processing/Filer.java: * @spec https://www.rfc-editor.org/info/rfc3986 RFC 3986: RFC 3986: Uniform Resource Identifier (URI): Generic Syntax