I independently discovered this bug for firefox-esr (Version: 52.9.0esr-1 from Debian Buster) when comparing rsync results with and without the --checksum option.
irwin@merlin> ls -l /usr/share/firefox-esr/browser/defaults/preferences total 100 -rw-r--r-- 1 root root 16101 Dec 31 2009 devtools.js -rw-r--r-- 1 root root 1738 Dec 31 2009 firefox-branding.js -rw-r--r-- 1 root root 72676 Dec 31 2009 firefox.js -rw-r--r-- 1 root root 238 Jun 26 15:29 vendor.js -rw-r--r-- 1 root root 2053 Dec 31 2009 webide-prefs.js And as previously explained the combination of those bad Dec 31 2009 dates on those files plus updates on three of them that only involve version numbers (so the length of the file is unchanged) is probablematic for rsync without the --checksum option. And most people avoid the --checksum option because it takes so much longer than running rsync without that option. Anyhow, I hope the availability of the "touch" fix that has been suggested before inspires someone from the team of maintainers for this package to fix this bug since giving the highest priority to all the easy bugs like this one should considerably simplify the list of outstanding bugs for firefox-esr. Alan __________________________ Alan W. Irwin Programming affiliations with the FreeEOS equation-of-state implementation for stellar interiors (freeeos.sf.net); the Time Ephemerides project (timeephem.sf.net); PLplot scientific plotting software package (plplot.sf.net); the libLASi project (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net); and the Linux Brochure Project (lbproject.sf.net). __________________________ Linux-powered Science __________________________