Brutalist architecture is a movement in architecture that flourished from the 1950s to the mid-1970s, descending from the modernist architectural movement of the early 20th century. The term originates from the French word for "raw" in the term used by Le Corbusier to describe his choice of material béton brut (raw concrete). (From https://en.wikipedia.org/wiki/Brutalist_architecture .)
Brutalist web design, similarly, is marked by a no-frills design philosophy, with function determining form. See http://brutalistwebsites.com/ for examples and news.ycombinator.com, https://codepen.io/brianhaferkamp/posts/feed/, etc. for discussion.
Brutalism now arrives for Tiki Wiki CMS Groupware in the form of the Pseudobrutal theme, "pseudobrutal" because, of course, underlying the spare appearance is the full Tiki foundation including the Bootstrap CSS framework, jQuery, kitchen sink . . . .
!! Installation
When the theme archive is expanded, its files will be in a directory (folder) that contains all the theme files in their necessary subdirectories. Install the theme by transferring this directory to the Tiki site's "themes" directory. On some systems, access permissions for the theme's directories and files might need to be configured. If so, use the same settings as for other theme directories on the server. After refreshing the site's Look and Feel admin page, the theme name will appear in the theme selector, and can be selected.
!! Fonts
This theme uses a webfont that is retrieved from Google Fonts. If the Tiki site doesn't have access to the Internet, or if there is some reason it shouldn't make the request for the font, then local storage of the font should be implemented.
!! Theme modification
The style sheet of this Tiki theme is compiled from Less files. For a particular site, the theme can be modified by editing the relevant Less partial and compiling the CSS. Or the CSS style sheet itself can be edited. Alternatively, a custom.css file in the themes directory will override any rules in the style sheet, or CSS rules can be input in the Custom CSS text area under the Customization tab of the Look and Feel admin page of the site's control panels.
For general help with Tiki themes, please use the forums at the Tiki themes forum , or ask in the Tiki IRC channel, etc.