disable or customise WP logout confirmation

Did you want to show a screenshot? If so, it’s not visible. Here’s how you can post screenshots here: https://wordpress.org/support/forum-user-guide/block-editor/#adding-screenshots

And yes, if you get a question like that, it’s definitely coming from a plugin. It would be interesting to at least see the text that’s displayed, especially if it’s in English—then you can search for it in the repository and identify the plugin if necessary. Alternatively, you would have to examine the source code that is displayed there. This should also help you find the plugin.

I think I log out of WordPress too rarely 😀 This is a feature in the WordPress core: https://developer.wordpress.org/reference/functions/wp_nonce_ays/

There are several ways to disable it.

• Via code, see: https://wordpress.stackexchange.com/questions/67336/how-to-log-out-without-confirmation-do-you-really-want-to-log-out or https://www.role-editor.com/forums/topic/user-logout-without-confirmation/
• Via plugin: https://wordpress.org/plugins/disable-woocom-logout-confirmation/