Just need something basic to open a few EML files, don't want to install Outlook or anything heavy for it.

Tried a couple things and ended up sticking with Kernel EML Viewer, does exactly what I need without any extra issues. Just opens the file and shows everything, sender, subject, body, attachments, and it's free. Handles a few files at once too if that's ever useful.

For more information - https://www.nucleustechnologies.com/eml-viewer.html