MDL-37356 it was noticed that it's still possible to introduce decimal commas "," in the database DB (mdl_data_content->content) for the latlong field type.
1) It may happen when importing records from CSV files.
2) It may happen when restoring a course backup containing them because of 1).
So it seems that this needs fix:
A) Clean all existing commas and convert them to points "."
B) Prevent CSV import to create contents with commas.
C) Prevent restore to create contents with commas.
And that's all. That way we'll be 99.99% sure that database DB contents always contains normalized decimal points, never commas.
While the issue is present in all branches... this should be considered a followup of
MDL-37356, hence should land only to master. If required, a backport issue may be created later (including both MDL-37356 and this).