[Bug] ".txt" is added at the end of the filename downloaded by Brave Android

[AnthillSudoku]

Describe the bug
".txt" is added at the end of the filename when downloading some files with Brave Android (at the receiving end).
This happens only with some filename's extensions or no extension at all.

Here few extensions I tested:

affected extensions:
.kdbx / .backup / no extension

non affected extension:
.jpg / .pdf / .webm / .txt

To Reproduce
Steps to reproduce the behavior:

1. Go to pairdrop.net
2. Send a .kdbx file to the android device with Brave (or one of the affected)
3. download the file with Brave
4. open the file manager and check the extension

Expected behavior
filename is unchanged

Desktop (please complete the following information):

• OS: debian 12
• Browser Firefox
• Version 128.5.0esr

Smartphone (please complete the following information):

• Device: samsung a52q
• OS: eOS (LineageOS)
• Browser Brave
• Version 1.73.97

Bug occurs on official PairDrop instance https://pairdrop.net/
Yes
Version: v1.10.10