At the very end of this section of the tutorial:
https://docs.godotengine.org/en/stable/getting_started/step_by_step/ui_code_a_life_bar.html#update-health-with-a-signal-when-the-player-takes-a-hit
There's this part:
func update_health(new_value):
number_label.text = str(new_value)
bar.value = new_value
When trying to run the game with F5 as it says, it doesn't work and the debugger says "Invalid set index 'value' (on base: 'TextureProgress') with value of type 'String'." I tried changing bar.value = new_value to bar.value = int(new_value) and it then worked, though I have no idea why. I'm looking at the Player.gd script and it's pretty clear that the health variable being emitted is an integer, not a string.
Just thought I would mention this for whoever maintains the tutorial webpages, this stumped me for at least an hour and I still don't know why it didn't work.