When you transfer files using mtp (for example to/from an android phone), run `journalctl -f` - you will see a lot of debug information of each file being transferred.
Example (I have removed some personal information):
```
kdeinit5[6792]: kde.kio-mtp: Copy file "file.jpg" from filesystem to device "/dir1/" "/dir2/"
kiod5[6576]: kf5.kiod.kmtpd: getFileMetadata: "/dir1/file.jpg"
kiod5[6576]: kf5.kiod.kmtpd: Match for parent found in cache, checking device. Parent id = 23
kiod5[6576]: kf5.kiod.kmtpd: Found parent in cache
kiod5[6576]: kf5.kiod.kmtpd: File not found!
kdeinit5[6792]: kde.kio-mtp: Sending file "/dir1/file.jpg" with size 41633
kiod5[6576]: kf5.kiod.kmtpd: sendFileFromFileDescriptor: "/dir2/file.jpg"
kiod5[6576]: kf5.kiod.kmtpd: getFileMetadata: "/dir1"
kiod5[6576]: kf5.kiod.kmtpd: Match found in cache, checking device
albert-5491 kiod5[6576]: kf5.kiod.kmtpd: Found file in cache
kdeinit5[6792]: kde.kio-mtp: Sent file
kdeinit5[6792]: kde.kio-mtp: fileSystemFreeSpace: QUrl("mtp:/device/Internal shared storage")
kiod5[6576]: kf5.kiod.kmtpd: storage info updated
```

This goes on for each file.

kio 5.73.0-1

Steps to reproduce:
Connect an mtp device, run journalctl -f and transfer a file. A large amount of log will be written for each file transferred.