LED lighting fixture driver busted - what can I replace it with?
Based on the input voltage in the picture being 200-240V, I'm guessing you're not in the US, but I could be wrong. Be aware of different rules that may apply based on where in the world you are.
When looking for a replacement LED driver, what is important?
A replacement driver should have a similar voltage input and output range, but what is more critical to match is the current supplied to the LEDs, as over current and over temperature tend to be what kills LEDs. If a direct replacement is not available, look for a driver with an adjustable current limit that you can change to match to the old value, by using a multimeter with a current measurement.
Where can I find a suitable driver to purchase, and how can I make sure it's safe?
Constant-current LED drivers are available from many electronics suppliers like DigiKey or Mouser (US examples, no affiliation). Be sure to select a reputable supplier that sells drivers with the relevant certifications (UL, CE, ETL, etc) and be wary of online marketplaces that may not have the same safety guarantees for what they sell.