I wanted to overwrite a large video file with a version that was encoded to a smaller size. The overwrite dialog told me the size difference was 16,0 EiB. I suspected some kind of overflow and could confirm as follows.

Steps to reproduce
1. Create two testfiles whose size differs in at least 2 GiB:
touch testfile1  # 0 byte
dd if=/dev/zero bs=1048576 count=2048 of=testfile2  # 2048 × 1 MiB
2. Try to rename testfile 1 to testfile 2 in Dolphin (or vice versa)

Expected result
The correct size difference should be shown (2 GiB).

Actual result
The difference is shown to be 16,0 EiB.

Additional information
If testfile2 is created with 2047 blocks of 1 MiB instead of 2048 blocks, the size difference is shown as 2,0 GiB.

Plasma 5.20.5
Frameworks 5.78.0
Qt 5.15.2