From the README.txt

  # dd the raw image to a medium of your choice (little less than 2GB)
  xzcat devuan_ascii_2.0.0_armhf_sunxi.img.xz | sudo dd of=/dev/mmcblk0 bs=2M  

I prefer using pv to see the progress:

  $ xz -tv devuan_ascii_2.0.0_armel_raspi1.img.xz # Get the size of the image
  devuan_ascii_2.0.0_armel_raspi1.img.xz (1/1)
  100 %     145,4 MiB / 1.891,0 MiB = 0,077    79 MiB/s       0:23
  $ xzcat devuan_ascii_2.0.0_armel_raspi1.img.xz | pv -s 1891M > /dev/sdX # replace X with the sdcard
  1,85GiB 0:03:21 [9,37MiB/s] [==========================================================>] 100%  

You need them if you want to query/fetch/build source packages. Some other unexpected things need to do that (like the nvidia drivers). I guess they might not need it but they do need kernel headers at least. But that's right for the most part you don't need them, but it's best to have them in case you forget. (based on comments by gnarface and pardis from #devuan on

For installing npm add the backports to your sources.list e.g.:

deb ascii-backports main non-free contrib
deb-src ascii-backports main non-free contrib

Using different kind of markup languages is not the way I like. pandoc converts from several markup languages to several markup languages. dokuwiki is supported as target only, not as source. To convert from pandoc's markdown to dokuwiki I use:

 pandoc -t dokuwiki -o mypage.dokuwiki

https sources in sources.list

After reading Kritische Sicherheitslücke in Debians Update-Tools I checked /etc/apt/sources.list and found my configuration with http:// “”. Since throws a warning in the browser that the certificate is only valid for I changed my sources to