The files in this directory are only used during Slint installation.
They are put here instead of in the main packages directory to avoid that
running the command
  slapt-get --install-set
install them in a Slint system.
Here is how they are built:
brltty-installer cd ../../source/brltty/ && fakeroot brltty-installer.SlackBuild
espeak-ng-installer cd ../../source/espeak-ng && mv SLACKBUILD.installer SLACKBUILD \
  && fakeroot slkbuild -x && mv SLACKBUILD SLACKBUILD.installer
espeakup-installer cd ../../source/espeakup && fakeroot sh espeakup-installer.SlackBuild
firmware-installer cd ../../source/kernel-firmware && sudo sh build_firmware-installer \
  && chown -R <regular user> *
installer-translations-slint cd ../../source/installer-translations && \
  fakeroot sh installer-translations.SlackBuild
links-installer cd ../../source/links && fakeroot sh links-installer.SlackBuild
modules-installer cd ../../source/kernel && build_modules-installer
slint-doc-installer cd ../../source/slintdocs && fakeroot slint-docs.SlackBuild [1]
w3m-installer cd ../../source/w3m && w3m-installer.SlackBuild
After having built each package remove the previous one in ../../slint/installer
  and associated metadata and move the new package there.
You can use the script ../../source/mtp.sh to do that

[1] The script slint-docs.SlackBuild builds 2 packages:
slint-doc-installer goes in this directory
slint-doc goes in the main packages directory