Example of working *Manage UI translations* add-on

I want to translate my add-on to my language. I’m having trouble configuring the Manage UI translations add-on on Blender 4.3 Linux, which is what the documentation says. I have tried with different Blenders (distro and flatpak).

On Rendering > I18n Update Translation I get the error “Could not init languages data!”, and clicking Init settings has no effect. Below is the current configuration for flatpak Blender:

Current configuration

Furthermore, the terminal I started Blender from shows lines like the following from almost any UI action:

/home/martin/Documentos/i18n
/app/blender/blender/locale/po
/home/martin/Documentos/i18n/blender.pot

The folder /home/martin/Documentos/i18n/ is writable. I have created blender.pot file inside it as an attempt to solve the issue. Setting File Paths > Development > I18n branches to a writable directory has been unsuccessful.

Does anyone have a working configuration?

(This was originally posted on blender.stackexchange. I was directed here.)