Unfortunately, there isn't a direct way to track the exact number of users utilizing this plugin, as it is embedded within Confluence pages. However, you can monitor the frequency of its usage and the specific pages where it is employed. Please refer to the steps outlined in the screenshot below to gain insights into the plugin's usage patterns.
Or you can perform an advanced search for the macro name (see below), giving you a general idea of how many pages it has been used on. This won’t consider pages you can’t see or if the App is used multiple times on a page.
Here is another process provided by Atlassian to search the usage of macros via API, refer to below documents
https://developer.atlassian.com/cloud/confluence/advanced-searching-using-cql/ https://developer.atlassian.com/cloud/confluence/rest/intro/#status-code
To use the API search function, you will need to add the below search after your instance URL. The first will give you all pages that have the HTML macro on it up to the 1st 25 uses. The second raises the limit to 250.
/wiki/rest/api/content/search?cql=macro=%27html-macro%27
/wiki/rest/api/content/search?cql=macro=%27html-macro%27&limit=250