Unable to install Python based extensions on Windows XP. LibreOffice provides Python 3.5 or this version cannot be used on Windows XP or earlier!
On Windows XP with LibreOffice 5.4.1 :
(LibreOffice 5.4.2 is incompatible with Windows XP see Bug 112928)
Steps to Reproduce:
1. Download Python based extensions like Grammalecte www.dicollecte.org/grammalecte/oxt/Grammalecte-fr-v0.5.18.oxt
2. Open LibreOffice 'Tools' 'Extensions Manager' 'Add'
User Profile Reset: Yes
User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:45.0) Gecko/20100101 Firefox/45.0
Created attachment 137140 [details]
A screenshot of error linked in comment 0
(attaching here an externally-hosted screenshot)
Windows XP and Windows Vista support is going to be dropped in LibreOffice 6.0 -> https://wiki.documentfoundation.org/ReleaseNotes/6.0#Windows
Being realistic, I don't think anybody is going to fix this.
OTOH, you can use LibreOffice 5.3.7 from https://www.libreoffice.org/download/libreoffice-fresh/
Closing as RESOLVED WONTFIX