Does ext4 support the sync mount option?

Question

linux

A couple of times stumbled upon the statement

Some Linux filesystems don't support -o sync and -o dirsync (the ext2, ext3, fat and vfat filesystems do support synchronous updates (a la BSD) when mounted with the sync option).

well
, or in Russian:

Note:
Keep in mind that not every file system supports all options.
For example, the sync option is currently only supported by ext2, ext3, fat, vfat and ufs file systems.

source
From this we can conclude that Ext4 stopped supporting sync. However, if we assume that these fragments of texts were written before the advent of Ext4, then this will not be the case. I can't find any confirmation of either hypothesis anywhere. Experiments with mounting an Ext4 partition with the mount -o sync command do not give errors, the mount output after that shows a line in which the sync option is taken into account, everything looks like it works for Ext4. Unfortunately, I did not find any real ways to check whether the disk is working in synchronous mode.

Answer 1

man mount did not try to read? Actually, that's where it should have started.

FILESYSTEM-INDEPENDENT MOUNT OPTIONS
       Some of these options are only useful when they appear in the /etc/fstab file.

       Some  of  these  options could be enabled or disabled by default in the system kernel.  To check the current setting
       see the options in /proc/mounts.  Note that filesystems also have per-filesystem specific default mount options (see
       for example tune2fs -l output for extN filesystems).

       The following options apply to any filesystem that is being mounted (but not every filesystem actually honors them –
       e.g., the sync option today has an effect only for ext2, ext3, fat, vfat and ufs):

Direct answer to the question asked.