1. QString QSystemDeviceInfo::productName() API description in documentation is incomplete.
The API description is missing the case part at the end of line. I suppose the missing part should be something like "an empty QString will be returned".

2. enum QSystemDeviceInfo::SimStatus
The enum description misformed, it may be something like "This enum describes the status of the sim card or cards.".

3. QSystemScreenSaver::QSystemScreenSaver()
Line "On platforms where there is no one default screensaver mechanism, such as Linux, this class may not be available." may not have "one" word in it.

4. QSystemNetworkInfo::currentCountryMobileCode()
Description has a "/" at end of line.

5. QSystemNetworkInfo:: currentMobileCountryCode() / currentMobileNetworkCode(), homeMobileCountryCode(), homeMobileNetworkCode(), locationAreaCode().
Check the description about the desktop case.

6. QSystemNetworkInfo::locationAreaCode()
Returns int but the desctiption says it returns an empty string.

7. QSystemNetworkInfo::Connected
This enum description is misspelled for network as "newtwork".

8. Please specify the returned values consistently for each API in most common cases, like for QSystemStorageInfo::logicalDrives() which does not say if the returned QStringList can be empty or
must have atleast one value present. QSystemNetworkInfo::cellId() return what value when network is not in online state.

Some suggestions to add in documentation:

1. QSystemDisplayInfo::colorDepth() and QSystemDisplayInfo::displayBrightness()
What is the expected value incase of screenNumber more than screenCount(), it would be good to mention it.

2. QSystemScreenSaver::setScreenSaverInhibit()
"Will be reverted upon destruction of the QSystemScreenSaver object." Does this line mean that if i set the inhibit from one object and verify it from another before destroying it, the inhibit
status is same on both objects. Or the inhibit status is independent to object. I could not understand it clearly from documentation.

3. QSystemNetworkInfo::interfaceForMode()
Incase when no interface is available for a particular network mode is the returned interface is a invalid network interface. May be we need to mention in the documentation about it.