Femtoscopic radii extracted in the present analysis (green solid circles), as a function of the cube root of the measured charged-particle multiplicity $\langle N_{\rm ch}\rangle^{1/3}$, at low (left) and high (right) $k_{\rm T}$ compared with published results from pp~ (red solid squares), p--Pb~ (green empty circles), and Pb--Pb~ (blue diamonds) collisions. Statistical (lines) and systematic uncertainties (boxes) are shown. The dotted (dashed) line shows the fit of the pp and p--Pb (Pb--Pb) data with a first-order polynomial.