As Shri Desiraju Hanumanta Rao says in his introductory note,
the Chitrashala Press Edition (1936) of Harivamsha with commentary of Nilakantha and edited by Pandit Ramachandrashastri Kinjawadekar has Bharata Savitri as the last content.
For those interested,
where you can download the sections in pdf format.
In the prAstAvikam, available at
you can find shri Kinjawadekar's reason for including Bharata Savitri.
In the text of Bharata Savitri he has given the pAThabheda-s he found in the manuscripts that he consulted.
IMHO there are many interesting shlokas in there.
As far as I know, very few scholars seem to be aware of it, apart from the ones cited by Shri Desiraju Hanumanta Rao.
Best
Harindranath