HR diagram M_G vs. (BP − RP) with Gaia magnitudes corrected for interstellar reddening. Left: distribution of all giant stars whose measured parallax S/N is higher than 5 (groups A and B), but that are impacted by a low level of interstellar reddening (E(B − V)≤0.15 mag, grey dots), a medium level (E(B − V)≤0.5 mag, pink dots), or an even higher level (0.5 < E(B − V)≤1.0 mag, orange dots). The positions of the known HdC and EHe stars that have passed the first selection cuts are indicated, as well as the newly discovered ones. Right: same as the left, except that the represented giant stars are those that have passed the first selection cuts. The black dots correspond to the objects impacted by a medium value of interstellar reddening, E(B − V)≤0.5 mag, while the red dots show those impacted by higher values up to 1.0 mag. The error bars on the y-axis due to the parallax measurement accuracy are shown only in the right diagram for clarity. The selection areas are marked with red lines: solid lines for groups A and B, and dashed lines for groups C and D, whose parallax is measured with an S/N lower than 5. The interstellar extinction of A_V ∼ 1 mag is represented with a black arrow.