Thank you for your reply.

I found /gnu/store/...-gtk+-3.24.0-bin/bin/gtk-update-icon-cache. Also found /gnu/store/...-glibc-2.28/bin/locale.

Why not these command make symlink to ~/.guix-profile/bin ?

And  I did gtk-update-icon-cache -t -f --include-image-data ~/.guix-profile/share/icons/hicolor.
It return permission error that is directory read only.

I use ja_JP.utf8 locale and man page garbled in some case. I do LC_ALL=C or posix man in that case. 

2019年1月11日(金) 9:01 Leo Famulari <leo@famulari.name>:
On Thu, Jan 10, 2019 at 10:23:15AM +0900, 荒井吉則 wrote:
> Hello,  I'm still beginner for GuixSd.
>
> I have installed epiphany but show error , missing hicolor-icon-theme.
> I have installed hicolor-icon-theme. No error message but show bookmark
> icon only, other icons missing.
>
> What is other icon-theme or another packages I need to install?

Not sure but try adwaita-icon-theme.

> I think missing icon cache but gtk-update-icon-cache command is missing too
> then install gtk+-3.24.0.
>
> Why gtk+-3.24.0 package don't include gtk-update-icon-cache etc commands?

gtk-update-icon-cache is in the "bin" output of GTK+. For example:

------
$ guix build gtk+
/gnu/store/0mskf7mzfrhrnkixfadrvvr5lgfssfzf-gtk+-3.24.0-bin
/gnu/store/iypmqb5a6g1f1xw4s7m88vy51hgyh0p1-gtk+-3.24.0-doc
/gnu/store/3yrx79ds64dabi6qkkmh4s7ydiqxhl4g-gtk+-3.24.0
$ ls -l /gnu/store/0mskf7mzfrhrnkixfadrvvr5lgfssfzf-gtk+-3.24.0-bin/bin
total 3984
-r-xr-xr-x 2 root root  134656 Dec 31  1969 broadwayd
-r-xr-xr-x 2 root root 1907384 Dec 31  1969 gtk3-demo
-r-xr-xr-x 2 root root 1551368 Dec 31  1969 gtk3-demo-application
-r-xr-xr-x 2 root root   81840 Dec 31  1969 gtk3-icon-browser
-r-xr-xr-x 2 root root  194488 Dec 31  1969 gtk3-widget-factory
-r-xr-xr-x 2 root root   41960 Dec 31  1969 gtk-builder-tool
-r-xr-xr-x 2 root root   22744 Dec 31  1969 gtk-encode-symbolic-svg
-r-xr-xr-x 2 root root   22544 Dec 31  1969 gtk-launch
-r-xr-xr-x 2 root root   31816 Dec 31  1969 gtk-query-immodules-3.0
-r-xr-xr-x 2 root root   21224 Dec 31  1969 gtk-query-settings
-r-xr-xr-x 2 root root   43584 Dec 31  1969 gtk-update-icon-cache
------