Imsc-Rosetta is a new IMSC/TTML compliant file format. It supports wide range of features and styling options as it's intended to serve as reliable intermediate when converting between various proprietary formats. In this respect, there are a lot of similarities between Imsc-Rosetta and EZTitles and a very few number of features/styles that are present in EZTitles but not in Imsc-Rosetta, or vice-versa.
Importing and Imsc-Rosetta file in EZTitles offers a single configuration option:
Enabling the Override Project Settings option may change your current Project Settings, as indicated on the image above. We recommend using the Override... option when the goal is to delivery subtitles that match the original Imsc-Rosetta file as close as possible.
Imsc-Rosetta, as mentioned earlier, supports wide array of features, styling options and effects applicable to Open and SDH Subtitles, Closed Captions and Japanese subtitling. The later include horizontal groups, ruby and bouten/emphasis annotations and vertically oriented subtitles. Full documentation of the supported features is available on their GitHub page.