Literal text means literal text
A period matches a period and a dollar sign matches a dollar sign. Neither search nor replacement interprets regular expressions, capture groups or replacement commands. An empty replacement removes matches. An empty search leaves the source unchanged.
Word boundaries are explicit
Whole word excludes matches immediately next to a Unicode letter, number or underscore. It is useful for matching cat without catalog. This is a character-boundary rule, not linguistic word segmentation for every language.
Matches do not overlap
Replacement walks through the original once. Inserted text is not searched again. Match case distinguishes uppercase and lowercase; otherwise Unicode case-insensitive matching is used. Replace the first match only stops after the first eligible occurrence.