It's help-about.png icon. It can be found here.
The color is not right - the help-about icon is the normal blue-and-white one; however the one used in Kexi is gray.
The color can be corrected. Just desaturate it, like Kexi does:
Result obtained using Krita
That did the trick I'm can't tell if it's an exact match, but it should be close enough. Thanks.