#axes.labelsize:   medium # fontsize of the x any y labels
#axes.labelpad:   4.0   # space between label and axis
#axes.labelweight:  normal # weight of the x and y labels
#axes.labelcolor:  black
#xaxis.labellocation: center # alignment of the xaxis label: {left, right, center}

import matplotlib.pyplot as plt

plt.plot([1, 1])
a = plt.xlabel("x")
print(a)
print(vars(a))
print(a._text)
print(plt.gca().get_xlabel())
plt.show()

Text(0.5, 0, 'x')
{'_stale': True, 'stale_callback': None, '_axes': None, 'figure': <Figure size 640x480 with 1 Axes>, '_transform': <matplotlib.transforms.BlendedAffine2D object at 0x0000019EC1471F98>, '_transformSet': True, '_visible': True, '_animated': False, '_alpha': None, 'clipbox': None, '_clippath': None, '_clipon': True, '_label': '', '_picker': None, '_contains': None, '_rasterized': None, '_agg_filter': None, '_mouseover': False, 'eventson': False, '_oid': 0, '_propobservers': {}, '_remove_method': None, '_url': None, '_gid': None, '_snap': None, '_sketch': None, '_path_effects': [], '_sticky_edges': _XYPair(x=[], y=[]), '_in_layout': True, '_x': 0.5, '_y': 0, '_text': 'x', '_color': 'black', '_fontproperties': <matplotlib.font_manager.FontProperties object at 0x0000019EC1471BE0>, '_usetex': False, '_wrap': False, '_verticalalignment': 'top', '_horizontalalignment': 'center', '_multialignment': None, '_rotation': None, '_bbox_patch': None, '_renderer': None, '_linespacing': 1.2, '_rotation_mode': None}
x
x

#axes.labelsize:   medium # fontsize of the x any y labels
#axes.labelpad:   4.0   # space between label and axis
#axes.labelweight:  normal # weight of the x and y labels
#axes.labelcolor:  black
#yaxis.labellocation: center # alignment of the yaxis label: {bottom, top, center}

import matplotlib.pyplot as plt

font = {'family': 'serif',
    'color': 'darkred',
    'weight': 'normal',
    'size': 16,
    }
plt.plot([1, 1])
plt.ylabel("y", fontdict=font, backgroundcolor='grey')

plt.show()