Sometimes for reference purposes, one needs to duplicate a paragraph (X) to paragraph Y, one can easily by copy paste, but in case he/she wants to modify Y and want that modification (or in that case every modification) to be reflected in X, he/she will have to copy-paste every time to update.
A feasible solution will be to 'clone' Y to X, that way if one changes X or Y, both of the paragraphs will be changed.
A cloned paragraph will be specified by a non-printable gray colored border which can be toggled on or off.
The navigator will have a list of cloned paragraphs.
Reproducible with LO 18.104.22.168 32bit (win10 Ent 64bit)