Hi.  Most likely the problem is my settings of Emacs.  But I do not know
what causes it.

After booting Emacs, (I am not sure if it is due to the state of idling), "[
]" appears around the name of mode.
For example, if it is the org-mode,

[[[...(org)...]]]

if it is the scratch buffer,

[[[...(Lisp Iteration)...]]]

This seems to appear to all modes simultaneously.
Seemingly it does not affect the continuation of my work, but it bothers
because I do not understand why it is happening.

Could anyone guess what is causing it?

Thanks in advance.

soichi