Elements of the sequence are the lines of the file, as delimited by the UNIX newline character ('\n'). The file content is treated as 8 bit binary text, with no assumptions or requirements on character encoding.
Note that the first line of the file is element 0, as defined by the Sequence interface API. Traditionally in a text editor a patch file the first line is line number 1. Callers may need to subtract 1 prior to invoking methods if they are converting from "line number" to "element index".