The paper presents new results of the ongoing study of the unusual Lynx-Cancer void galaxy DDO 68 with record-low-metallicity regions ( 12+ \log ( O/H ) \sim 7.14 ) of the current star formation ( SF ) .
They include : a ) a new spectrum and photometry with the 6-m SAO RAS telescope ( BTA ) for the Luminous Blue Variable ( LBV = DDO68-V1 ) .
Photometric data sets are complemented with those based on the Sloan Digital Sky Survey ( SDSS ) and the Hubble Space Telescope ( HST ) archive images ; b ) the analysis of the DDO 68 supergiant shell ( SGS ) and the prominent smaller H \alpha arcs/shells visible at the HST image coupled with kinematics maps in H \alpha obtained with the Fabry-Perot interferometer ( FPI ) at the BTA ; c ) the list of identified at the HST images of about 50 most luminous stars ( -9.1 < M _ { V } < -6.0 mag ) related to star-forming regions with the known extremely low O/H .
This is intended to pave the path for the actual science with the next generation of giant telescopes .
We confirm the earlier hints on significant variations of the LBV optical light deriving its amplitude of \Delta V \gtrsim 3.7 mag for the first time .
New data suggest that in 2008–2010 the LBV reached M _ { V } = –10.5 and probably underwent a giant eruption .
We argue that the structure of star-forming complexes along the SGS ( ‘ Northern Ring ’ ) perimeter provides evidence for the sequential induced SF episodes caused by the shell gas instabilities and gravitational collapse .
The variability of some DDO 68 luminous extremely metal-poor stars can be monitored with medium-size telescopes at sites with superb seeing .