This is the master switch (on by default) for your self-serve catering storefront, found on the Order: Catering tab of Client Config as "Catering: Allow Online Ordering." Turn it off and:

• Every customer-facing catering ordering page (starting a catering order, viewing an individual catering meal page) redirects customers back to the homepage.
• In the admin Catering Menu builder, the actions that actually change your catering menu — saving it, adding preset meals, adding random meals — are blocked and bounce you back to the dashboard. Simply viewing or deleting items from the builder still works.
• The Catering module itself stays installed and its settings remain editable — this only disables the public ordering flow, which is useful if you want to sell catering exclusively through Proposals/quotes instead.