Strange that they went with plain text when the industry is converging on (newline delimited) JSON logs for structured data. This also serves as the backbone of observability with metrics and tracing also being folded into and output as JSON.
Call them events and you can claim all the event-sourcing buzzwords too.
I wouldn't put too emphasis on the plain text — we started logging back when carrying everything via JSON would've been going against the grain. These days it might've gone the other way (I'm not sure).
One point that I'd try to convey is that the canonical line technique works for any kind of structured format. We use logfmt in all our examples, but JSON would work just as well.
Call them events and you can claim all the event-sourcing buzzwords too.