Technical Term
RGI (Recommended for General Interchange)
The subset of emoji sequences that the Unicode Consortium recommends for support across all platforms.
In-depth Analysis
RGI stands for Recommended for General Interchange. It ensures that when you send an emoji from an iPhone, it will likely be recognized and displayed on an Android or Windows device. Sequences not in the RGI set might appear as a series of separate characters (e.g., a "tofu" or broken boxes).