['<code>/{,<i>n</i>}/</code>', 'empty lower bound quantifier is accepted as shorthand for 0'],
['<code>\x{ … }</code>', 'insignificant space within curly braces, also for <code>\b{}</code>, <code>\g{}</code>, <code>\k{}</code>, <code>\N{}</code>, <code>\o{}</code> as well as <code>/{m,n}/</code> quantifiers'],
['<code>0o0</code>', 'octal prefix <code>0o</code> alternative to <code>0…</code> and <code>oct</code>'],
['<code>/{,<i>n</i>}/</code>', 'empty lower bound quantifier is accepted as shorthand for 0'],
['<code>\x{ … }</code>', 'insignificant space within curly braces, also for <code>\b{}</code>, <code>\g{}</code>, <code>\k{}</code>, <code>\N{}</code>, <code>\o{}</code> as well as <code>/{m,n}/</code> quantifiers'],
['<code>0o0</code>', 'octal prefix <code>0o</code> alternative to <code>0…</code> and <code>oct</code>'],