magnetic reconnection theory. To find the footprints of QSLs, we would need vector magnetic field measurements and/or extrapolation of the magnetic field configuration to the upper atmosphere, which would be beyond the scope of this simplistic study. Therefore we further studied only a gradient of the longitudinal magnetic field as a proxy for those regions by means of polarity inversion regions. showed that the QSLs are usually found around polarity inversion lines. By eye we had a feeling that the CP flare kernels are located in regions with very strong magnetic field gradients, whereas C1 flares in regions, where the magnetic field gradient is not so strong and the field has often a diffuse character. Examples of active regions and detected flare kernels for CP and C1 flares are shown in Figs. \[fig:examples\_nonflat\] and \[fig:examples\_flat\], respectively. To confirm or reject the hypothesis, we investigated the value of the gradient of the longitudinal magnetic field $B_{\rm los}$, which is normalised by the maximum of the field in the field-of-view. Hence we studied the value $$f({ {\mathbf r} })=\frac{|\nabla B_{\rm los}({ {\mathbf r} })|}{{\rm max}_{{ {\mathbf r} }} |\nabla B_{\rm los}({ {\mathbf r} })|},$$ where ${ {\mathbf r} }$ is a positional 