I just noticed I erased my css changes on the core files by updating jve.
I thought it would be nice if it was possible to override JVE's output as it is a content plugin.
I saw that it would mean a tmpl folder in the plugin files of JVE docs.joomla.org/Layout_Overrides_in_Joom...erriding_a_Plugin.29
Well it's nothing important as I can put the css I use for jve in my template css.
It is just a suggestion
Never make changes in the files of the package because they will always be overwritten in possible update processes. If you want to change CSS instructions, then use a custom CSS file of your template that is update safe (such as custom.css).
I know that it is possible to exclude the output in a template file but IMO it makes no sense for JVE because the CSS class and ID names are essential for the functionality of the plugin. If the user changes it in a template override, then the plugin won't work properly any more.