  In the 90's, theoretical studies motivated the use of the asymptotic-giant
branch bump (AGBb) as a standard candle given the weak dependence between its
luminosity and stellar metallicity. Because of the small size of observed
asymptotic-giant branch (AGB) samples, detecting the AGBb is not an easy task.
However, this is now possible thanks to the wealth of data collected by the
CoRoT, Kepler, and TESS space-borne missions. It is well-know that the AGB bump
provides valuable information on the internal structure of low-mass stars,
particularly on mixing processes such as core overshooting during the core
He-burning phase. In this context, we analysed ~ 4,000 evolved giants observed
by Kepler and TESS, including red-giant branch stars and AGB stars, for which
asteroseismic and spectrometric data are available. By using statistical
mixture models, we detected the AGBb both in frequency at maximum oscillation
power and in effective temperature. Then, we used the Modules for Experiments
in Stellar Astrophysics MESA stellar evolution code to model AGB stars and
match the AGBb occurrence with observations. From observations, we could derive
the AGBb location in 15 bins of mass and metallicity. We noted that the higher
the mass, the later the AGBb occurs in the evolutionary track, which agrees
with theoretical works. Moreover, we found a slight increase of the luminosity
at the AGBb when the metallicity increases, which complicates the use of the
AGBb as a standard candle. By fitting those observations with stellar models,
we noticed that low-mass stars (M < 1.0 $M_{\odot}$) require a small core
overshooting region during the core He-burning phase. This core overshooting
extent increases toward high mass, but above M > 1.5 $M_{\odot}$ we found that
the AGBb location cannot be reproduced with a realistic He-core overshooting
alone, and instead additional mixing processes have to be invoked.
