how to download the previous version files

[siming]

Hello,
    how to download the previous version files?  For example, I want to 
download the base-files_10.3+deb10u5.dsc, but at 
http://ftp.debian.org/debian/pool/main/b/base-files/ 
    it just have the newest file base-files_10.3+deb10u6.dsc.
   Thanks.
    SIMING