title: "Missing Mono Script" and "The referenced script (Unknown) on this Behaviour is missing" errors
body: <p>I'm following a tutorial to make a 2D platformer. I installed the bayatGames asset package and wanted to run the 'demo' project they created. However, I get multiple errors saying the same thing: &quot;The referenced script (Unknown) on this Behaviour is missing!&quot;. From what I understand, the script that's meant to be attached to these objects is not available, but I don't understand why? I haven't edited the asset package, this is just how it was downloaded. (<a href="https://i.stack.imgur.com/WbBBb.png" rel="nofollow noreferrer">picture of what my project looks like</a>) this error also means I can't see the character's objects on my screen. What's causing this issue? The unity version I am running is 2019.3.15f1.</p>