@Find 'string' in 'container'
Type: Agent

First paragraph: the string. Second paragraph: container (of any distance). Here, the agent’s text field is the control panel—container followed by content.
Actual name: agentFind
This agent collects notes inside of container whose text contains string—both are conveniently set by typing them into the text window.
Enter string as the first paragraph and container as the second.
Query only
descendedFrom($Text(agent).split("\n").at(1)) &$Text.contains($Text(agent).split("\n").at(0))
Thus if you type this:

To find notes whose text contains “consent” inside of Computing, type this.
… the result will be this:

Notice the agent’s nice display expression.
This agent’s custom display expression comes from c_agentFind_DE:
Display expression
(if($AgentPriority!=-1){"@"}else{"• "}) + "Find " + "'" + ($Text.split("\n").at(0)) + "' in '" + ($Text.split("\n").at(1)) + "' [" + $ChildCount + "]"