hugo/docs/content/en/functions/strings/Contains.md

title	description	categories	keywords	action	aliases
strings.Contains	Reports whether the given string contains the given substring.			aliases related returnType signatures functions/strings/ContainsAny functions/strings/ContainsNonSpace functions/strings/HasPrefix functions/strings/HasSuffix functions/collections/In bool strings.Contains STRING SUBSTRING	/functions/strings.contains

{{ strings.Contains "Hugo" "go" }} → true

The check is case sensitive:

{{ strings.Contains "Hugo" "Go" }} → false