> gerund: a form that is derived from a verb but that functions as a noun, in English ending in -ing, e.g., asking in do you mind my asking you?.

They're just casual or conversational forms of the verbs. Dropping "is" from "is updating" for example.

That's technically true. The typical interpretation would be "[The] site [was] not found" as a verb. If you squint hard enough you can interpret is as "[The] site [is] not [in the state of being] found".