It is in js-file for InfoBubble. I just use it. It is not mine, but as I today investigate, the last release of this library was about 6 years ago. And today it contains only change to https in source file and there is no new compiled.
I suggest to open file (save it before for backup)
com_zhgooglemap\site\assets\js\infobubble\trunk\infobubble-compiled.js in text editor.
Find and change http: to https:
And it will work.
In next release I try download this image and save local copy in extension and change js library file to use it