Please help us help you and fill where relevant:
Your LimeSurvey version: LimeSurvey Community Edition Version 6.5.13+240617
Own server or LimeSurvey hosting: Own with Debian 11
Survey theme/template: very barely modified fruity twentythree
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I have a file upload question which allows .gz, .gzip, .schematic and some more. However, when I upload a .schematic file, I get an error saying " Sorry, unable to check extension of this file type application/gzip". Can anyone help me? Do I need to provide logs or something here?

Seems gzip are not included in github.com/LimeSurvey/LimeSurvey/blob/ma...s/fileExtensions.php or github.com/LimeSurvey/LimeSurvey/blob/ma...s/fileExtensions.php

1. Create tour own fileExtensions and set it magic_file config (you can merge with current one)
2. Report the issue : community.limesurvey.org/bug-tracker/