Currently editors are able to insert 3 digits max after the comma in the float field type. Steps
In a float field type
1. Insert a float number with more than 3 digits after decimal point and publish your change
2. In the view of the content we can see there is more than 3 digits after the decimal point
3. Edit the same content: the float number is rounded to 3 digits after the decimal point
It would be nice to have the possibility when editing a content type / field type to set the number of digits after the decimal point on top of min and max value.