Browser on my Mac opens twitch automatically

Then you probably should be in the Developer section and not the section for reporting issues with using the forum software. Thy this:

https://discussions.apple.com/community/developer_forums

I still think Twitch is far more likely to help you with this. App-specific questions here about third-party products can take a long time for the right person to see it.

I'm not trying to run you off but, after 20+ years here, I have a pretty good sense of what does and does not work in this user-to-user setting. I only want you to find the most effective help for your issue.

Neither FireFox nor Twitch is an Apple product. Questions about non-Apple products in an Apple-supported forum can take weeks to get a response, if any. Apple is not here; we are a community of end users.

Best action: Start with Twitch support. FireFox support will have no more idea of how the Twitch login works than do we.

zamboknee wrote:

Thank you, Allan. I will hit up the 'developer' section.

Things seemingly involved: Firefox.

Some things seemingly not involved in this question: app development and the developer forum, and seemingly also Twitch.

If your question is about how to prevent Firefox from opening a web page when you first launch Firefox, and you no longer want to view that web page, check the app settings within Firefox.

First, check the home page setting: https://support.mozilla.org/en-US/kb/how-to-set-the-home-page

If this is not your Firefox home page setting, and involves Firefox launching automatically when you first log in, then check your login items in  > System Settings > General > Login Items — in versions prior to Ventura, the login items are in  > System Preferences > Users & Groups > select your user > Login Items

If I have not correctly understood your question, or the above does not resolve this, please post back here.