Well, that is certainly not ready to be put in the release repo. I can't even read Help-> Documentation, or Help-> Release notes. The pictures seem fine, but the text consists of a line, or blank. I tried on more than one system, with the same results.
This has nothing to do with Dooble or Chromium or Qt. It's the fontconfig (mis)configuration. The Ghostscript libraries (used by CUPS if you have it installed) install some really outdated legacy PostScript fonts like Nimbus which are not Unicode aware. This broken Nimbus is then used as a default (!) font in the system (because of some fontconfig magic). But even if you would get rid of it, you still have outdated non-Unicode Type1 Times New Roman font supplied by OS/2 since ages which gets selected as a default for the "serif" family by fontconfig. And since Chromium/Qt/Google requests "serif" as the standard font for web content by default, Times New Roman gets selected and this makes many pages (including Dooble Documentation) lack any text. Note that if you remove this Times New Roman (TNR.PFB) and friends from /PSFONTS, the mentioned Nimbus will be selected for "serif" with the same effect — lack of Unicode support.
A proper solution is to fine-tune fontconfig for OS/2 so that it ignores Type1 in favour of modern TTF (e.g. ArcaOS comes with the nice Droid family IIRC which works just fine with Dooble). But this isn't an easy task, it needs time to sort things out. As a time being, there are two possible workarounds:
1. Install a well-known font family that has a higher priority in fontconfig (the DejaVu family works great here). This is a preferred solution as it will fix not only Dooble but any Qt/Chromium application.
2. Go to Dooble Settings, Web page, Fonts group, and replace all Nimbus/Times New Roman entries with Droid or any other font that works with Unicode (i.e. not standard OS/2 Type1 fonts).
Perhaps worth mentioning in the Readme.
PS. You can easily check which font Qt will use for a given family request by doing `fc-match FAMILY` on the command line. You may need to run `fc-cache -f` to rescan your fonts after you toss them around.
PPS. Here's the fontconfig ticket, for future reference
https://github.com/bitwiseworks/fontconfig-os2/issues/1