2.3.1 Preamble Section

• A file may contain at most one preamble.
• The preamble, if any, is a consecutive sequence of lines beginning with the first line in the file.
• The first line of the preamble must begin with a hash (#) character.
• Subsequent lines of the preamble must either begin with a hash, or immediately follow a line that ends with a backslash (\) character (or both).