I’ve been using __FILE__ for years, but I never thought to look for its siblings.
echo ' line:'. __LINE__ .' file:'. __FILE__ .' directory:'. __DIR__ .' function:'. __FUNCTION__ .' class:'. __CLASS__ .' method:'. __METHOD__ .' namespace:'. __NAMESPACE__;
I feel as though I should have noticed these earlier; they’re clearly referenced in the docs for debug_backtrace(), after all.