"Clear recent documents" and "Clear unavailable files" remove all files or the currently not available, respectively. Since pinned documents are supposed to persist for some time it's likely that users want to keep them. Removing pinned documents needs to be done either on the item itself or by unpinning first.
It is the case in: Version: 24.2.0.0.alpha0+ (X86_64) / LibreOffice Community Build ID: e912bc63ddbac584678571c85fdb74a368366874 CPU threads: 16; OS: Windows 10.0 Build 19045; UI render: Skia/Raster; VCL: win Locale: en-AU (de_DE); UI: en-US Calc: CL threaded
Andreas Heinisch committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/core/commit/71cae3a219ff1629368b8f324d0de89afc9445e9 tdf#155698 - Start Center: Retain pinned items when clearing the list It will be available in 24.2.0. The patch should be included in the daily builds available at https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: https://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.
Working well in 24.2. Thanks, Andreas. Version: 24.2.0.0.alpha0+ (X86_64) / LibreOffice Community Build ID: defc3dd75ff8ff937d2161237b281284240b86f0 CPU threads: 16; OS: Linux 6.2; UI render: default; VCL: gtk3 Locale: ro-RO (ro_RO.UTF-8); UI: en-US Calc: threaded