HTML Class generation assumes "class safe" names
Bringing this issue over from the iATS extension page where there are images and more documentation. Indications are that this also affects WordPress sites.
In short, html classes that are generated for the iATS extension and possibly other contexts assume the machine name is class safe. If the name has spaces ("iATS Payments Credit Card" rather than "iATS_Payments_Credit_Card"), it results in multiple classes (.iATS .Payments .credit .card) rather than the single class (.iATS_Payments_Credit_Card).
A primary problem with this is that if the standard .card class is used on a site (very common with bootstrap), it leads to formatting problems for elements with Civi-generated classes. Otherwise this issue might fly under the radar on most sites.
Joomla! 3.9.24, Civi 5.39.0, iATS extension 1.7.4