strace beim starten von FF liefert mir diese Ausgabe:
read(16, "pref(\"distribution.searchplugins"..., 238) = 238
read(6, "ilitystatus=\"1\"/>\n </pluginIt"..., 8192) = 8192
read(6, " </pluginItem>\n <pluginIte"..., 8192) = 8192
stat("/home/benutzer12345/.mozilla/firefox/B567Sa22.default/pluginreg.dat", {st_mode=S_IFREG|0600, st_size=2899, ...}) = 0
open("/home/benutzer12345/.mozilla/firefox/B567Sa22.default/pluginreg.dat", O_RDONLY) = 6
access("/home/benutzer12345/.mozilla/firefox/B567Sa22.default/plugins", F_OK) = -1 ENOENT (No such file or directory)
access("/home/benutzer12345/.mozilla/plugins", F_OK) = 0
open("/home/benutzer12345/.mozilla/plugins", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 6
access("/usr/lib/firefox-esr/browser/plugins", F_OK) = -1 ENOENT (No such file or directory)
access("/usr/lib/mozilla/plugins", F_OK) = 0
open("/usr/lib/mozilla/plugins", O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC) = 6
lstat("/usr/lib/mozilla/plugins", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/lib/mozilla/plugins/flash-mozilla.so", {st_mode=S_IFLNK|0777, st_size=34, ...}) = 0
readlink("/usr/lib/mozilla/plugins/flash-mozilla.so", "/etc/alternatives/flash-mozilla."..., 4095) = 34
readlink("/etc/alternatives/flash-mozilla.so", "/usr/lib/adobe-flashplugin/libfl"..., 4095) = 44
lstat("/usr/lib/adobe-flashplugin", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/lib/adobe-flashplugin/libflashplayer.so", {st_mode=S_IFREG|0644, st_size=16480480, ...}) = 0
lstat("/usr/lib/mozilla/plugins", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0
lstat("/usr/lib/mozilla/plugins/libjavaplugin.so", {st_mode=S_IFLNK|0777, st_size=39, ...}) = 0
readlink("/usr/lib/mozilla/plugins/libjavaplugin.so", "/etc/alternatives/mozilla-javapl"..., 4095) = 39
lstat("/etc/alternatives/mozilla-javaplugin.so", {st_mode=S_IFLNK|0777, st_size=64, ...}) = 0
readlink("/etc/alternatives/mozilla-javaplugin.so", "/usr/lib/jvm/java-8-openjdk-amd6"..., 4095) = 64
stat("/usr/lib/adobe-flashplugin/libflashplayer.so", {st_mode=S_IFREG|0644, st_size=16480480, ...}) = 0
stat("/usr/lib/adobe-flashplugin/libflashplayer.so", {st_mode=S_IFREG|0644, st_size=16480480, ...}) = 0
stat("/usr/lib/adobe-flashplugin/libflashplayer.so", {st_mode=S_IFREG|0644, st_size=16480480, ...}) = 0
access("/usr/lib/firefox-esr/distribution/searchplugins", F_OK) = 0
access("/usr/lib/firefox-esr/distribution/searchplugins/common", F_OK) = 0
access("/usr/lib/firefox-esr/distribution/searchplugins/locale/en-US", F_OK) = -1 ENOENT (No such file or directory)
access("/usr/lib/firefox-esr/distribution/searchplugins/locale/en-US", F_OK) = -1 ENOENT (No such file or directory)
access("/home/benutzer12345/.mozilla/firefox/B567Sa22.default/searchplugins", F_OK) = -1 ENOENT (No such file or directory)
kann sein das, dass ein oder andere Verzeichnis nun abweicht vom ersten Post, wegen viel hin und her probieren