As a Roblox developer, it is currently too hard to tell that you’ve saved your local plugin during development correctly. When you right click on your plugin in the explorer and choose Save as Local Plugin, it opens a save dialog that will either display exclusively .rbxmx files if you have selected a folder, or .lua files if you have selected a script.
I accidentally saved my plugin by right clicking on the script instead of the folder yesterday, so every time I opened a file in Studio I would get a nonsense error from what looked like the plugin I was developing, and I failed to figure out what had happened until I manually opened the plugin folder myself in explorer and saw a duplicate of the plugin i was developing saved as .lua.
Because scripts are saved as .lua files instead of .rbxmx, they lose all of their children without any feedback given to the user (bad UX!!!), so I did not notice the mistake right away. I went on to continue working on the plugin and saved it correctly next time, but because the save dialog did not show all of the contents of the plugin folder, I did not see the accidentally saved .lua file.
All files, or at least both .lua and .rbxmx should be shown in the save dialog regardless of what kind of instance you are attempting to save as a plugin.
Really though, scripts should just be saved as .rbxmx in the first place.
If Roblox is able to address this issue, it would improve my development experience because I would not need to waste time glaring in confusion at an error that doesn’t line up with my code, completely unknowing that there was an old version of my plugin in my plugins folder mistakenly saved without its children.