Trouble with Customs

Hi,

happy new year 2026!

My project "Kraft" (https://volle-kraft-voraus.de) is using Akonadi 
Contacts for a long time. It basically queries contacts from akonadi 
using the ContactFetchJob. The code is

https://github.com/dragotin/kraft/blob/master/src/addressproviderakonadi.cpp#L105

Now I tried to read customs from the Addressee class which were set in 
KAddressbook, for example a Tax number of a customer. That works 
basically, however, the title of the custom field title does not return 
in "cleartext"  but as the key of the contactmetadata which I figured 
from akonadiconsole.

My question is how I can "decode" the custom field title? Somehow I need 
to use the contactmetadata from AkonadiItem, but I can not quite figure 
how to code that in the Kraft code referenced above.

Can anybody here give me a hint?

Thanks a lot,

Klaas