How to Check Through The Source Code of an RPM, with systemd as an example:

Rocky Linux 9.6 systemd Source Code Review

  • I pulled the latest systemd source RPM for Rocky Linux 9.6:
wget https://dl.rockylinux.org/pub/rocky/9/BaseOS/source/tree/Packages/s/systemd-252-51.el9_6.1.src.rpm
  • Extracted the contents of the source RPM:
rpm -ivh ./systemd-252-51.el9_6.1.src.rpm
  • Built the systemd RPM:
rpmbuild --nodeps -bp ~/rpmbuild/SPECS/systemd.spec
  • Confirmed that indeed 20% of RAM is used in Rocky Linux 9.6:
grep TMPFS_LIMITS_RUN /home/howard/rpmbuild/BUILD/systemd-252/src/shared/mount-util.h
#define TMPFS_LIMITS_RUN             ",size=20%,nr_inodes=800k"

Updated: