Okay, so I am building a Google Maps blueprint - like the one in my screenshot below;
As you can see, one can enter the Latitude / Longitude in the panel - and I used the default numbersfield for those fields (so one can not accidentally enter a non-numeric value) for the coords.
However, the standard numberfield does only accept rounded numbers, like 1 - 5 - 42 - 94594, etc… and I need a number with some floating points (is that correct English? I mean the numbers “after” the dot / comma (depends on your metric-system of course), like 52.442342 - 13.442352, etc…
The default settings for a numberfield have the html-step value defined as 1, meaning you can not enter a proper lat. / long. decimal.
Is it possible to override this single option, without creating a new numberfield (I solved it by copy/paste the whole number-directory with it’s contents to my /site/field directory and adjust the setting like in the screenshot below;
Of course this does do the job 
but maybe there is an option to override the default behaviour, without the need to copy the complete field to your own site-directory?
May be in the config.php file, or something (some settings looks like the are defined with a config-option, while others don’t).