Doesnt help but that text string is coming directly from the browser and not Joomla.

The message is a form validation message generated by the browser based on the min max values for the input

If you do NOT specify a min value in the field then the code generated will still have a min value of 1 - hence the message

If however you set the min value as -200 in the field then the code generated will have a min value of -200 and the message will change to reflect that

[note for anyone looking at this the message is a validation error message so you will only see it if you enter a numeric value outside of the min-max range for the field]

After adjusting the Plugin settings I now see a hover message that says Please select a valid value. The two nearest valid values are -186 and -185. This is for a field set to -185.85. And if you enter 10e3 and save you get back 10000.

Worse, if you have a real number set, such as -185.85, you can lose it by touching the increment/decrement buttons. It seems to be a bad idea to provide increment/decrement steps on a real number.

The PR that created the Number field was #43974

yes increment values are a bad idea for your use case.

If you dont want them then use a text field with the appropriate filter

I came across this problem whilst revising the Documentation for Joomla 6 and I am wondering what we might tell our audience!

No idea but there is no bug

No idea but there is no bug

Thanks for your input on this. It seems to me the Number field does not do anything you can't do with a text field. However, I have updated interim user documentation here: https://jdocmanual.org/en/jdocmanual?article=user/fields/adding-custom-fields-number-field - we are not putting anything in MediaWiki just now, amongst other things its image handling is broken.