The ISVForce category of the 2019 Partner Program Policies would apply here:
A Partner application that integrates to or makes use of any application, service or other product for which Partner collects fees is not a free application. (For example, an application is not a free application if it is provided under a “freemium” payment model or if it requires purchase of another application from the applicable Partner.) SFDC reserves the right in its sole discretion and at any time to determine whether an application is a free application for the purposes of these Program Policies
Trialware requires the following process:
To create trials on the AppExchange, your app or component must:
Be a managed package
Be managed via the License Management Application
Autoprovision—that is, the user must not need to interact with you at any point to get the app or component up and running
Have passed the security review
Have passed the Trialforce template review
In addition, a Chrome extension which is not listed on the AppExchange but uses developer edition APIs would probably fall under the freemium
language in the MSA:
You are Commercially Distributing Your Application if installation, access, and/or use of any version of Your Application or its features and capabilities require the payment of fees of any kind to You (including, e.g., if Your Application integrates to or makes use of any application or other product or service for which You collect fees, or if the Your Application is provided under a "freemium” payment model).
References