Actually, 'tuple display' is in the index under 'display' and links to the last paragraph in 6.2.3.  However, except for the index name, that paragraph doesn't use the phrase 'tuple display'.  So it gives the definition without saying what it is defining.

> Note that tuples are not formed by the parentheses, but rather by use of the comma operator. The exception is the empty tuple, for which parentheses are required — allowing unparenthesized “nothing” in expressions would cause ambiguities and allow common typos to pass uncaught.