How to reproduce:
1. Create a new project
2. Import the files from "Dialogue Databases.zip"

Actual result: Unity crashes.

Reproducible with: 2019.3.0a7, 2019.3.0a6.
Not reproducible with: 2019.3.0a5, 2019.3.0a1, 2019.2.0b8, 2019.1.8f1, 2018.4.3f1.

Notes:
In Unity 2019.3.0a5 error is thrown:

Unable to parse file Assets/Dialogue Databases/Dirk Woodchip (Auto-Backup).asset: [Parser Failure at line 188894: Expect ':' between key and value within mapping]
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)

A failed assertion is thrown before crash:
Assertion failed on expression: 'IsScalar()'

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Fixed in 2019.3.0a11