Plots: change in `savefig()`?

When saving figures from Plots, I use savefig(). In the past, savefig("figfile.svg") saved the figure in a file named figfile, with file extension svg.

Today, savefig("figfile.svg") saves the file in a file named figfile.svg with extension png.

  • Why this change?
  • How do I specify the file type now?