Error message in Terminal window

Since recently Blender from buildbot has gotten talkative; terminal is where all messages are thrown. Some seem having sense, some are clearly caused by addons.
Recently i’ve run into message

ID user count error: IMmyAddedFilename.hdr (from '[Main]')

after dropping in World’s HDRi replacement in file where image was not included. Blender gracefully crashed several times on preview while i was adjusting mapping of the image.

Now i’m in a doubt - it’s me as a user or Blender? I’m pretty sure i selected file from Blender’s File manager only once and it was used just in one image node. After file save there are no crashes but terminal still repeats this line, not sure which operation causes this tho.