Did you just find a file that has a digital signature from The Qt Company Oy? If that's the case, please read on.
You will typically notice The Qt Company Oy when clicking to run the file. The publisher name is displayed as the "Verified publisher" in the UAC dialog as the screenshot shows:

You can view additional details from the The Qt Company Oy certificate with the following procedure:
Here is a screenshot of a file signed by The Qt Company Oy:

As you can see in the screenshot above, Windows states that "This digital signature is OK". This implies that the file has been published by The Qt Company Oy and that no one has tampered with the file.
If you click the View Certificate button shown in the screenshot above, you can see all the details of the certificate, such as when it was issued, who issued the certificate, how long it is valid, etc. You can also examine the address for The Qt Company Oy, such as the street name, city and country.
Entrust Extended Validation Code Signing CA - EVCS1 and thawte SHA256 Code Signing CA has issued the The Qt Company Oy certificates. You can also view the details of the issuer by clicking the View Certificate button shown in the screenshot above.
The following are the The Qt Company Oy files I have collected, thanks to the FreeFixer users.At the moment there's no scan result available for any of the The Qt Company Oy files, but they have been queued for scanning. Please reload this page in 5-10 minutes to check if the scan result is available.
| Detection Ratio | File Name |
|---|---|
| Queued for scan.. | Qt5Network.dll |
| Queued for scan.. | qwindowsvistastyle.dll |
| Not available | qt-unified-windows-x86-2.0.3-1-online.exe |
| Not available | Qt5Gui.dll |
The analysis is done on certificates with the following serial numbers: