about:memory Instantbird (after minimizing memory usage)

Main Process

Explicit Allocations
757.32 MB (100.0%) -- explicit
├──397.48 MB (52.48%) ── heap-unclassified
├──220.53 MB (29.12%) -- js-non-window
│  ├──158.07 MB (20.87%) -- compartments
│  │  ├──156.54 MB (20.67%) -- non-window-global
│  │  │  ├───74.82 MB (09.88%) -- compartment([System Principal], jar:file:///C:/Program%20Files%20(x86)/Instantbird/omni.ja!/components/imConversations.js)
│  │  │  │   ├──54.90 MB (07.25%) -- gc-heap
│  │  │  │   │  ├──27.09 MB (03.58%) -- shapes
│  │  │  │   │  │  ├──13.65 MB (01.80%) ── tree
│  │  │  │   │  │  └──13.44 MB (01.77%) ── base
│  │  │  │   │  ├──22.57 MB (02.98%) -- objects
│  │  │  │   │  │  ├──13.02 MB (01.72%) ── function
│  │  │  │   │  │  └───9.55 MB (01.26%) ── non-function
│  │  │  │   │  └───5.24 MB (00.69%) ++ (4 tiny)
│  │  │  │   ├──18.00 MB (02.38%) -- shapes-extra
│  │  │  │   │  ├──16.00 MB (02.11%) ── compartment-tables
│  │  │  │   │  └───2.00 MB (00.26%) ── tree-shape-kids
│  │  │  │   └───1.92 MB (00.25%) ++ (4 tiny)
│  │  │  ├───43.70 MB (05.77%) -- compartment([System Principal], resource:///modules/jsProtoHelper.jsm)
│  │  │  │   ├──18.42 MB (02.43%) ── string-chars
│  │  │  │   ├──15.89 MB (02.10%) -- gc-heap
│  │  │  │   │  ├───8.62 MB (01.14%) ── strings
│  │  │  │   │  └───7.27 MB (00.96%) ++ (6 tiny)
│  │  │  │   ├───9.24 MB (01.22%) ── objects/slots
│  │  │  │   └───0.14 MB (00.02%) ++ (4 tiny)
│  │  │  ├───25.23 MB (03.33%) -- compartment([System Principal], jar:file:///C:/Program%20Files%20(x86)/Instantbird/omni.ja!/components/twitter.js)
│  │  │  │   ├──12.78 MB (01.69%) ++ (5 tiny)
│  │  │  │   └──12.45 MB (01.64%) ── string-chars
│  │  │  └───12.79 MB (01.69%) ++ (118 tiny)
│  │  └────1.53 MB (00.20%) ++ no-global/compartment(atoms)
│  ├───61.01 MB (08.06%) -- gc-heap
│  │   ├──51.07 MB (06.74%) ── decommitted-arenas
│  │   └───9.93 MB (01.31%) ++ (3 tiny)
│  └────1.46 MB (00.19%) ++ runtime
├───51.75 MB (06.83%) -- gfx
│   ├──43.58 MB (05.76%) ── font-charmaps [48]
│   ├───7.98 MB (01.05%) ── font-list [48]
│   └───0.19 MB (00.02%) ++ (3 tiny)
├───44.70 MB (05.90%) -- window-objects
│   ├──26.40 MB (03.49%) -- top(chrome://instantbird/content/instantbird.xul, id=26)/active/window(chrome://instantbird/content/instantbird.xul)
│   │  ├──17.33 MB (02.29%) -- layout
│   │  │  ├──10.06 MB (01.33%) ── pres-shell
│   │  │  └───7.27 MB (00.96%) ++ (6 tiny)
│   │  └───9.07 MB (01.20%) ++ (4 tiny)
│   └──18.30 MB (02.42%) ++ (6 tiny)
├───33.82 MB (04.47%) ── xpconnect
└────9.04 MB (01.19%) ++ (10 tiny)

Other Measurements
149 (100.0%) -- js-compartments
├──147 (98.66%) ── system
└────2 (01.34%) ── user

236.01 MB (100.0%) -- js-main-runtime
├──173.54 MB (73.53%) -- compartments
│  ├───97.99 MB (41.52%) -- gc-heap
│  │   ├──35.72 MB (15.14%) -- objects
│  │   │  ├──21.22 MB (08.99%) ── non-function
│  │   │  └──14.50 MB (06.14%) ── function
│  │   ├──30.43 MB (12.89%) -- shapes
│  │   │  ├──15.20 MB (06.44%) ── tree
│  │   │  ├──14.27 MB (06.05%) ── base
│  │   │  └───0.96 MB (00.41%) ── dict
│  │   ├──13.02 MB (05.52%) ── strings
│  │   ├──12.54 MB (05.31%) ── unused-gc-things
│  │   ├───5.04 MB (02.14%) ── type-objects
│  │   └───1.24 MB (00.53%) ++ (3 tiny)
│  ├───31.90 MB (13.52%) ── string-chars
│  ├───21.18 MB (08.97%) -- shapes-extra
│  │   ├──18.13 MB (07.68%) ── compartment-tables
│  │   └───3.05 MB (01.29%) ++ (3 tiny)
│  ├───18.76 MB (07.95%) -- objects
│  │   ├──16.87 MB (07.15%) ── slots
│  │   └───1.90 MB (00.80%) ++ (2 tiny)
│  └────3.71 MB (01.57%) ++ (6 tiny)
├───61.01 MB (25.85%) -- gc-heap
│   ├──51.07 MB (21.64%) ── decommitted-arenas
│   ├───7.45 MB (03.16%) ── unused-arenas
│   ├───2.48 MB (01.05%) ── chunk-admin
│   └───0.00 MB (00.00%) ── unused-chunks
└────1.46 MB (00.62%) ── runtime

107.93 MB (100.0%) -- js-main-runtime-gc-heap-committed
├───87.94 MB (81.48%) -- used
│   ├──84.89 MB (78.66%) ── gc-things
│   ├───2.48 MB (02.30%) ── chunk-admin
│   └───0.56 MB (00.52%) ── arena-admin
└───19.99 MB (18.52%) -- unused
    ├──12.54 MB (11.62%) ── gc-things
    ├───7.45 MB (06.90%) ── arenas
    └───0.00 MB (00.00%) ── chunks

0 (100.0%) -- low-memory-events
├──0 (100.0%) ── physical
└──0 (100.0%) ── virtual

29.23 MB (100.0%) -- window-objects
├──19.92 MB (68.15%) -- layout
│  ├──10.63 MB (36.38%) ── pres-shell
│  ├───3.53 MB (12.08%) ── frames
│  ├───2.26 MB (07.73%) ── style-contexts
│  ├───1.73 MB (05.92%) ── rule-nodes
│  ├───0.80 MB (02.72%) ── style-sets
│  ├───0.76 MB (02.62%) ── line-boxes
│  └───0.21 MB (00.70%) ++ (2 tiny)
├───9.04 MB (30.95%) -- dom
│   ├──4.07 MB (13.92%) ── element-nodes
│   ├──2.44 MB (08.34%) ── text-nodes
│   ├──2.42 MB (08.29%) ── orphan-nodes
│   └──0.11 MB (00.39%) ++ (3 tiny)
└───0.26 MB (00.91%) ++ (2 tiny)

  757.33 MB ── explicit
    0.00 MB ── gfx-d2d-surfacecache
    0.00 MB ── gfx-d2d-surfacevram
    0.00 MB ── gfx-d2d-vram-drawtarget
    0.00 MB ── gfx-d2d-vram-sourcesurface
   12.82 MB ── gfx-surface-image
    4.39 MB ── gfx-surface-win32
          0 ── ghost-windows
  596.59 MB ── heap-allocated
  976.27 MB ── heap-committed
  379.68 MB ── heap-committed-unused
     63.64% ── heap-committed-unused-ratio
    2.12 MB ── heap-dirty
  940.41 MB ── heap-unused
    0.03 MB ── images-content-used-uncompressed
  159.00 MB ── js-gc-heap
          0 ── low-commit-space-events
1,172.18 MB ── private
1,162.22 MB ── resident
    3.35 MB ── storage-sqlite
1,893.30 MB ── vsize