Build, test, and debug regular expressions
This regex matches either the exact string "abc" (due to the anchors ^ and $) or the literal string "i10n", which is a numeronym for "internationalization". It is useful for validating inputs that must be exactly one of these two specific values, or for simple pattern matching in text processing. The alternation (|) allows two distinct alternatives, with anchors applying only to the first alternative. Note that "i10n" is matched without anchors, so it can appear anywhere in a larger string.