Warrning message and access restriction by developers

I have installed a template that has a feature to enable and disable Powered by Nopcommerce.
this site still in testing and is not for public use . but I got a warning message in my admin regarding the powered by nopcommerce ...and in warning stated they can restrict access to the application .
now question is how secure is this app and what other information developers have access to .. I am not developer  ,so i can no audit the source code .. but normally such message means no restriction  access to back end and thus access to data .
please let me know if my assumption is correct or not before i can continue with further investment both time and financial to this app.
Thanks.

Of course, we cannot disable your website remotely. nopCommerce is an open-source solution, so you can always check that how it works.

But please note that all users of nopCommerce should meet our license terms. If someone wants to remove "powered by nopCommerce" text, then he needs a valid removal key.

As emphasized by Andrei, nopCommerce is an open-source, complimentary eCommerce platform. This implies that if you're not a developer, you can engage a professional agency or a freelance expert to establish your eCommerce store using nopCommerce. The entire project, including the source code, is freely accessible. However, in support of maintaining this open-source ecosystem, nopCommerce kindly requests a modest contribution. This is in the form of a license fee for the removal of the "Powered by nopCommerce" branding, which you can acquire here: nopCommerce Copyright Removal Key.

As an established nopCommerce Gold Solution Partner and an experienced offshore agency, we've been closely working with nopCommerce for several years. We can vouch for its robust security. The nopCommerce team does not have any access to your backend or data. When you see news updates on your admin dashboard, these are sourced from the nopCommerce server via a feed, ensuring no unauthorized interventions or data extractions are possible.

Personally, my journey with nopCommerce began in 2011, and I've been closely following its development before initiating NopAdvance. To my recollection, it's been a considerable time since any critical vulnerability has been reported in the system.

I trust this information and our endorsement will reinforce your confidence in nopCommerce. Have a great weekend!

Warm regards,
Atul