Irony in its broadest sense, is a rhetorical device, literary technique, or event characterized by an incongruity, or contrast, between reality (what is) and appearance (what seems to be). It is further defined into three major categories: verbal, dramatic, and situational.
Verbal Irony is an incongruity between what is said and what is meant.
Dramatic Irony is an incongruity between what a character in a work of fiction believes to be true and what the audience knows to be true.
Situational Irony is an "incongruity between the actual result of a sequence of events and the normal, [intended], or expected result."
The discordance of verbal irony may be deliberately created as a means of communication (as in art or rhetoric). Dramatic irony communicated the importance of a particular truth by portraying a person who is strikingly unaware of it, emphasizing a perceived truth. Descriptions or depictions of situational irony, whether in fiction or in non-fiction, serve the communicative function of sharpening or highlighting certain discordant features of reality. Verbal, dramatic, and situational irony are often used for emphasis in the assertion of a truth. The ironic form of simile, used in sarcasm, and some forms of litotes emphasize one's meaning by the deliberate use of language which states the opposite of the truth — or drastically and obviously understates a factual connection.
No written method for indicating irony exists, though an irony punctuation mark has been proposed. In the 1580s, Henry Denham introduced a rhetorical question mark or percontation point which looks like a reversed question mark. This mark was also proposed by the French poet Marcel Bernhardt at the end of the 19th century to indicate irony or sarcasm.
(wikipedia.org)
The irony here refers to the cache name.