What does "(卐)" as part of 两分字元 mean?

Question

The site zisea likes to give a two-part component breakdown of every character.

One of their classifications comes with a (卐) next to it.

For instance:

敢 is split up like:

两分字元：耳(卐) 攵

殷 is split up like:

两分字元：厂(卐) 殳

橐 is split up like:

两分字元：十(卐) 木

The entry for the character 卐 itself doesn't allude to this usage:

拼音wan4

古代印度宗教的吉祥标志。显现金光，如来佛胸前有卐字。中国唐代武则天定音为【万】。义为“吉祥万德之所集”。佛经中又写作【卍】。

What does "(卐)" as part of 两分字元 mean?

Answer 1

On http://zisea.com/zslf.htm# you can see this:

卐=难拆字元

So it is just a "symbol" used on the site to represent parts that are hard to identify.

It is not universal.