Many links to documentation are broken

[wollmers]

A quick check with an invalid URL in the current branch rel-10_0:

$ grep -Ri --exclude-dir={.git} 'doc.otobo.org/doc/' . | wc -l
     229

Needs a commitment to an URL scheme stable over longer periods.

Needs coordination across all repositories, websites and tool chains.

See RotherOSS/doc-otobo-admin#3

[svenoe]

Tidying