Thank you! I've added to the placeholders and will add more over time as well, with the full list here (see Available Placeholders section):
https://fearlessfrog.github.io/MSFS_Universal_Announcer/generated.html
Because there are quite a lot of possible simbrief things to add, I've also added a special 'xml' placeholder type, so you can get everything you need from that without me adding it:
So ‘xml’ will just say it verbatim, ‘xml_digits’ will read each digit (good for a flight numbers etc) and ‘xml_number’ will use more human sounding number formats, e.g. ‘1024’ is then said as ‘one thousand and twenty four’.