Strange "mount" parameters with ntfs3

My systems runs on ext4, but I have a media mounted with NTFS file system, because at times it needs to be read in W10.I am running 22.04.I read about a change in the file system drivers, with a relatively new ntfs3 in the kernel, instead of the userland ntfs-3g. I decided to try it, and changed the line in fstab from

/dev/disk/by-uuid/BE8A61EB8A61A11F /my/dir ntfs-3g uid=1000,gid=1000,dmask=022,fmask=133,ro,noauto 0 0

to

/dev/disk/by-uuid/BE8A61EB8A61A11F /my/dir ntfs3 uid=1000,gid=1000,dmask=022,fmask=133,ro,noauto 0 0

That is, just replacing ntfs-3g by ntfs3.I umounted and re-mounted. It was successful, though with a strange output of mount. Before it was

/dev/sdb2 on /my/dir type fuseblk (ro,relatime,user_id=0,group_id=0,default_permissions,allow_other,blksize=4096)

Now it is

/dev/sdb2 on /my/dir type ntfs3 (ro,relatime,uid=1000,gid=1000,fmask=37777600133,dmask=37777600022,iocharset=utf8)

It looks closer to *nix, I'd say, with the intended uid and gid. What I fail to understand, however, are the values for fmask and dmask.And what does the iocharset do here for me? Where does it come from?

Appreciate any explanation, thanks in advance!