Quoting Dr. Nikolaus Klepp (dr.klepp@???):

> Well, it's not. Try for yourself:
>
> # echo "/some/binary" > /proc/sys/kernel/hotplug
> bash: /proc/sys/kernel/hotplug: No such file or directory

Well....

root@mini:/proc# /bin/true > /proc/sys/kernel/hotplug
root@mini:/proc#


> /proc/config.gz is gone for ages, too.

root@mini:/proc# stat /proc/config.gz 
  File: ‘/proc/config.gz’
  Size: 30307         Blocks: 0          IO Block: 1024   regular file
Device: 3h/3d    Inode: 4026531985  Links: 1
Access: (0444/-r--r--r--)  Uid: (    0/    root)   Gid: (    0/    root)
Access: 2017-06-26 02:39:23.069018610 -0700
Modify: 2017-06-26 02:39:23.069018610 -0700
Change: 2017-06-26 02:39:23.069018610 -0700
 Birth: -
root@mini:/proc#

{shrug} I'm reporting only what I'm seeing in front of me. Above is a
Debian-testing system in a virtual machine on my laptop, originally
installed using an aptosid ISO file. (This is the same VM system I
used in researching
http://linuxmafia.com/faq/Debian/openrc-conversion.html before
repointing it to 'testing' instead of what was then 8.0/stable.
Thus the Aptosid-compiled binary kernel:

root@mini:/proc# uname -r
2.6.39-3.slh.1-aptosid-amd64
root@mini:/proc#


FWIW, Aptosid was a really cool project[1], dormant since a 2013 release
(http://distrowatch.com/table.php?distribution=Aptosid). Its close
cousin Siduction is still healthy:
http://distrowatch.com/table.php?distribution=Siduction

[1] Quarterly installable live CD ISOs based on sid=unstable +
stablising packages.