The game crashes when trying to load a resource pack with invalid syntax. For example, the following doesn't have quotes around the json element names:

{
replace:"false",
values:[
"nicknackgus:speedometer/tick"
]
}

This was saved at

/datapacks/speedometer/data/minecraft/tags/functions/tick.json

Reloading the data packs did not cause a crash until I attempted to enable the data pack. I expected to receive an error instead of a crash. I also expected the json file to be loaded in lenient mode, and not throw an error for missing quotation marks, but understand if the quotation marks are required.