TYPO3 Core

The default configuration file is correct. The help text is also right.
See source:typo3/sysext/core/Configuration/DefaultConfiguration.php#L224
When the value is not specified in the LocalConfiguration.php or AdditionalConfiguration.php files, it is set to -1.

However, with the current context and configuration presets, there is a configuration merging happening when using the install wizard.
The wizard go through setting features using source:typo3/sysext/install/Classes/Configuration/FeatureManager.php. It includes a Context feature which loads the presets into the configuration depending on the current context.

If in Production context, which is the default, the Production preset is loaded. It defines displayErrors to 0.
If in Development context, the Development preset is loaded. It defines displayErrors to 1.

Well yes. "Default setting" in this context means: If no setting is defined in LocalConfiguration at all. So, technically, the current description is correct, even if the "normal" install process usually sets an explicit value for this setting.

I tend to reject this issue at the moment.

I propose to simply adjust the text slightly and add that information about -1 being the fallback if nothing is defined at all.

Christian Kuhn wrote:

Well yes. "Default setting" in this context means: If no setting is defined in LocalConfiguration at all. So, technically, the current description is correct, even if the "normal" install process usually sets an explicit value for this setting.

I tend to reject this issue at the moment.

Mhm, even I can understand that interpretation, I think it's not useful to stick on it.
What is the value 0 then? standard but not default?
Sounds a bit like hairsplitting for me, at least it's not intuitive.