https://paste.the-compiler.org/view/883ead0c

brief: qutebrowser (not QtWebEngineProcesses) eats up 4gb with ~10 tabs opened at any time after a few days of usage

```
top - 19:12:34 up 4 days, 21:59,  1 user,  load average: 2.43, 1.38, 1.06
Tasks: 307 total,   1 running, 305 sleeping,   1 stopped,   0 zombie
%Cpu(s):  6.9 us,  1.1 sy,  0.0 ni, 85.9 id,  5.8 wa,  0.2 hi,  0.2 si,  0.0 st
MiB Mem :   7699.0 total,    242.0 free,   5656.8 used,   1800.2 buff/cache
MiB Swap:   8192.0 total,   7187.5 free,   1004.5 used.   1018.9 avail Mem 

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND                                                        
    799 leon      20   0 4971164   1.4g 180888 S  10.3  18.3 475:16.01 qutebrowser                                                    
    552 leon      -2   0 4045608 760712  87456 S   0.0   9.6 113:36.62 kwin_wayland


£ free -h
              total        used        free      shared  buff/cache   available
Mem:          7.5Gi       5.5Gi       236Mi       721Mi       1.8Gi       1.0Gi
Swap:         8.0Gi       1.0Gi       7.0Gi
```

closing qutebrowser and waiting one minute
the process is still there

```
top - 19:13:39 up 4 days, 22:00,  1 user,  load average: 2.00, 1.43, 1.10
Tasks: 260 total,   1 running, 258 sleeping,   1 stopped,   0 zombie
%Cpu(s):  2.9 us,  2.9 sy,  0.0 ni, 70.6 id, 22.1 wa,  1.5 hi,  0.0 si,  0.0 st
MiB Mem :   7699.0 total,   4018.5 free,   2945.2 used,    735.3 buff/cache
MiB Swap:   8192.0 total,   8009.3 free,    182.7 used.   4252.2 avail Mem 

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND                                                        
    799 leon      20   0 3965036   1.3g  69720 D   6.2  17.2 475:24.53 qutebrowser                                                    
    552 leon      -2   0 4027380 759212  85776 S   6.2   9.6 113:38.20 kwin_wayland
```

and finally, after 2:something minutes, the process vanishes.

```
£ free -h
              total        used        free      shared  buff/cache   available
Mem:          7.5Gi       1.6Gi       5.1Gi       224Mi       765Mi       5.4Gi
Swap:         8.0Gi       125Mi       7.9Gi
```

on to another start.
here's debug from right after startup (~0.6GB used by qutebrowser):

```
>>> summary.print_(tr.create_summary())
                            types |   # objects |   total size
================================= | =========== | ============
                      <class 'str |      114265 |     11.03 MB
                     <class 'dict |       15340 |      5.92 MB
                      <class 'set |         566 |      2.87 MB
                     <class 'code |       12283 |      2.11 MB
                     <class 'type |        1461 |      1.49 MB
                     <class 'list |       13735 |      1.24 MB
          <class 'sip.wrappertype |         979 |   1022.01 KB
             <class 'sip.enumtype |         709 |    736.70 KB
     <class 'sip.methoddescriptor |       12298 |    576.47 KB
                    <class 'tuple |        8624 |    508.20 KB
       <class 'wrapper_descriptor |        6346 |    446.20 KB
                  <class 'weakref |        4404 |    309.66 KB
  <class 'collections.OrderedDict |         940 |    306.73 KB
                      <class 'int |        6901 |    205.95 KB
        <class 'getset_descriptor |        2842 |    177.62 KB
```

this is a few hours later (1.7GB used by qutebrowser):

```
>>> tr.print_diff()
                             types |   # objects |   total size
================================== | =========== | ============
                       <class 'str |        5716 |    536.97 KB
                      <class 'list |         462 |     94.95 KB
                      <class 'dict |         170 |     38.49 KB
        <class 'PyQt5.QtCore.QSize |         325 |     33.01 KB
                     <class 'tuple |         375 |     28.05 KB
  <class 'functools._lru_list_elem |         327 |     17.88 KB
                      <class 'code |           0 |     16.67 KB
                   <class 'weakref |          82 |      5.77 KB
         <class 'functools.partial |          72 |      5.62 KB
                    <class 'method |          86 |      5.38 KB
         <class 'PyQt5.QtCore.QUrl |          44 |      4.47 KB
                 <class 'frozenset |           1 |      4.21 KB
                       <class 'int |         129 |      3.53 KB
   <class 'PyQt5.QtCore.QByteArray |          34 |      3.45 KB
             <class 'random.Random |           1 |      2.49 KB
```